Bottom Feeder Required

In a tank that size, a bristlenose plec would work well. I think it is one of those plecs that like to graze on bogwood.

The only reason I can think of for not going with platies is that it can lower the pH and hardness of the water and platies like it hard and alkaline. However, if your water is quite hard it should also have high KH which will resist changes in pH so I wouldn't worry about that aspect.
The profile on here for bristlenoses says they like to eat the micro-organsism that grow on bogwood, which is why the profile recommends there should be a piece of wood in the tank. It doesn't have to be a very big piece.

Not sure exactly how bogwood could be difficult for cleaning up, though did you mean the bristlenose? All plecs, and all algae eaters for that matter, do poo a lot. It goes with the diet I'm afraid.

I have hard alkaline water and bogwood has very slight reduced my pH. I haven't noticed any difference in hardness. I did a lot of research when choosing my plant décor and the most obvious downside with bogwood is that it can stain the water when you first introduce it to the tank. You can get around this if its an issue by pre-soaking the bogwood, boiling it or adding carbon to your filter. Some people like the tea coloured water and many fish also prefer it. I would not worry about adding bogwood to your tank, provided its from a reputable source.

With regards to bottom dwellers/algae eaters, the bristlenose pleco is a fine choice. Peaceful, widely available and won't get too large. The clown pleco is another possibility if you are after one algae eating machine!

Alternatively you could get a shoal of Otocinclus or Pitbull Plecos (Paratocinclus jumbo), though the latter are difficult to find.

Due to the small size of my tank, I went with an army of Red Cherry Shrimp and some Nerite Snails. The shrimp keep my plants immaculate and my nerites are great at keeping my glass and bogwood clean.

Good point on the Otos, was thinking more of their algae eating abilities! I'd love to get some Pitbull Plecos but haven't the room or seen them at any of my LFS.