Hello :)

A warm welcome to the forum, @DrawingDrake 

Good to read of your tank inhabitants, and glad that they have names (I also name my fishes).  Also congratulations on successfully growing food for the fish.

My immediate thought on reading of your inhabitants and learning of your plans to get more tanks is that Yelena would very much appreciate more ember tetra friends - ember tetras are a shoaling species.  I'd definitely advise having 6+ (or, better still, 8-10) ember tetras in one tank, of at least 60x30cm (24"x12") footprint in size. 
Can you find out what your water hardness (in CaCO3/ppm or German degrees hardness) is?  We can then advise whether the two endlers (or ideally a shoal including several more) might work well in that same tank.

Male betta are usually best in a tank on their own - they can suddenly 'turn' on their tankmates which you might only notice when one is dead or suddenly missing.

I'm not very familiar with the other species you have, so others here may be able to advise better. 
In the meantime, though, take a look at the following species requirements which tell you more about them and their requirements - this might also help inform what size of tanks you'll need to get once you have moved:
https://www.seriouslyfish.com/species/crossocheilus-langei?utm_content=cmp-true
https://www.seriouslyfish.com/species/synodontis-petricola/
https://www.thinkfish.co.uk/fish/ember-tetra.html and https://www.seriouslyfish.com/species/hyphessobrycon-amandae/ (more comprehensive and up-to-date info)
https://www.thinkfish.co.uk/fish/endlers-livebearer.html
https://www.thinkfish.co.uk/fish/siamese-fighting-fish-male.html

Looking forward to reading more of your plans / fishtank developments, and hope this is helpful in the interim. 

Apologies for having been unable to reply again before today and that no-one else has been around to help either.

You can test your water hardness with a test kit that measures GH and KH; this might be helpful too https://www.thinkfish.co.uk/calculators/hardness-conversion  Alternatively, your water supplier website may have details for your area or zip code.
Water hardness levels (ie how soft or hard the water is) is far more important than PH.  Once you’ve tested those levels, we should be able to advise further.

The general “rule of thumb” is not to house fish together where one might fit in another’s mouth – I’d be concerned about the embers and endlers ending up as snacks or some species.

Convict cichlids: https://www.thinkfish.co.uk/fish/convict-cichlid.html or the more comprehensive and up-to-date https://www.seriouslyfish.com/species/amatitlania-nigrofasciata/ should be useful for requirements and potentially appropriate tankmates.

In a nutshell, I think Bob needs his own tank (eg the 10g), the embers and endlers will need their own tank (or two separate, depending on your water hardness levels), and the convict cichlid will likely need its own tank with larger tankmates.

I don’t know what tank availability or suppliers are like in the US but these might give some inspiration:
https://www.swelluk.com/aquarium/fish-tanks-and-decor/fish-tanks
https://www.completeaquatics.co.uk/aquarium-accessories/aquarium-tanks-and-cabinets

Hope that helps.

thanks everyone for your responses. i ordered a gh/kh test kit in the mail and will post results when i test. i think my tap water is usually pretty hard (calcium builds up near faucets if theyre not cleaned well) but im not opposed to buying distilled water or even an RO machine if thats necessary to reach the needed softness. in the meantime i got some indian almond leaves and i put one in to see if that will lower the pH a bit but im not sure if i should take out the activated carbon?

currently the plan for after the move is looking something like keeping the 10 gallon, adding a 29 gallon and a 55 gallon as well. we bought the standard Aqueon 29 and 55 gallon tanks (https://www.petco.com/shop/en/petcostore/product/aqueon-standard-glass-aquarium-tank-29-gallon) since they were on sale and we will be storing the 55 gallon until the move. the 29g is cycling presently and when its ready the cichlid will go in there until the move. then the cichlid will move into the 55g with some larger tank mates, possibly the existing petricola plus a couple others since it needs a group. id also like to get maybe some giant danios (?). truthfully id love to get another cichlid, maybe a firemouth, but im wary of overstocking the 55g since they can be territorial. i want the 55g to be heavily hardscaped with lots of rocks and caves.

truthfully i am not concerned about Bob attacking the tetras since i have never seen them interact. also, Bob has very long fins and is much slower than the tetras even if they did get close. im considering maybe having Bob and a tetra shoal (plus maybe if i can find a catfish that likes softer water and will stay under 4 inches? i like having a "clean up" fish to help eat any forgotten food) in the 29g with lots of little hidey spaces in case they do need to flee. in that case id put the endlers in the 10g maybe with some other livebearers, smaller fish, and/or perhaps shrimp (idk much about shrimp so id do way more research but theyre cute lol). this way the 10g can have harder water and the 29g have softer water? should i do it the other way around, with the soft water fish in the 10g and a hard water community in the 29g?

as for the algae eater i dont think my roommates will be cool with two 50+ gallon tanks so i may need to rehome her. i can see if my school's aquarium will take her since they already have a few siamese algae eaters or find another student with a tank at home that can take her.

sorry for longer paragraphs this time and thanks again for your help (:

alright, i took out the carbon i've scrolled planetcatfish before because i like looking at pictures especially of the corycats bc theyre just so cute lol but ill certainly look around for a catfish suitable for my tank

tank GH is 7 drops on the API kit which it says is 125.3ppm.
dechlorinated tap water GH is only 3 drops which it says is 53.7ppm
regular tap water GH is 4 drops, or 71.6ppm
what does it mean that the GH in the tank is higher than the tap GH? could it be because ive begun feeding artemia so im adding small amounts of salt water? (i try to strain the artemia as mush as possible so its only a few ml per feeding but could that make a difference?) does GH or KH matter more, and whats the ideal hardness i should be aiming for right now given that some of my organisms want hard water and some want soft?

tank KH is 8 drops/degrees or 143.2ppm
i meant to test the KH for dechlorinated and regular tap as well, but my hands started to get irritated from handling the regents so ill test those tomorrow and report back.

im like 99% sure eleven is a siamese algae eater bc she's already like 3 inches long. also, her head and mouth aren't very catfish-shaped and her stripes are very smooth and not at all mottled like the pictures of otocinclus i've seen. i dont think ive seen an otocinclus in person but the SAEs at school look just like her (except skinnier i think). i can see if i can add a picture of her if you'd like to verify but i dont think otocinclus get as big as she already is.
i am very sad to hear that i may have to rehome her though, since she's super cute and i love watching her munch on the algae. i had some brown algae before i got her that was super annoying to scrape off and thats completely gone now. recently though i have noticed her acting a little erratic so i think more space would do her good. do you think i could keep her with maybe two other SAEs in the 55g? the cichlid hardness range overlaps with siamese algae eater a bit but seriouslyfish does say they do better in bigger groups and of course i want whats best for her, especially because the school aquarium is primarily a learning environment so fish-fatal mistakes happen pretty often. i guess i dont have to make a decision on it right away, but advice would be appreciated.

and id like to think im pretty knowledgable but the most consistent thing i seem to be learning on this journey is how much i truly *dont* know yet so thanks again for all your help (: