Is It OK To Just Have 2 Gourami

I have no experience with gourami at all and so the following is based more on hunch. However, I've checked the Thinkfish Fish Profiles and also another reputable source https://www.seriouslyfish.com/species/trichopodus-trichopterus/ and I'm wondering if the theory behind this is due to the tendency for males to squabble. Bearing that in mind, and that these fish are generally not considered good community fish, my inkling would be that sticking to the 2 you have would be preferable than potentially ending up with a large number of males and likely more aggression and also problems for other tank inhabitants. If need be or behaviours change, you can always add at a later stage - but I'd be inclined not to "upset the apple cart" if all's ok most of the time. Other may wish to correct me if they have more knowledge/experience on this.

Is one more dominant than the other? Do you know if they’re male or female? it’s hard to tell from the pictures.

Sue is right, but also peaceful coexistence isn’t unheard of so there’s also something to be said for not upsetting the apple cart.

If they’re not actually fighting, and if one isn’t having to run away from the other one, I’d probably leave them... but there’s always a chance you might have to separate them in the future.

Gouramies are related to Bettas and it’s that kind of “this is my patch” aggression that they have to a lesser degree. Adding a few more would crowd them, which sometimes works and sometimes doesn’t.

I've been hiding indoors with the curtains closed. Luckily the tanks haven't got higher than 26 deg.

Blowing air over a tank does cool it a bit - as long as the lid is open. The moving air evaporates the water; evaporation takes energy - in the form of heat from the tank water. Latent heat of vaporisation. But it won't cool the water by much.