Smaller tanks, due to their limited water capacity, any slight change in the environment can be significant here compared to bigger tanks. I would advice having a heavily planted tank or at least planted nano tanks which at least help to stablise the water (personal experience). Anyway it looks nicer for a nano planted tank compared to a nano fish only tank.
Equipment like Sunfire said, can use HOF and clip on light/light with stand. Get those low maintenace plants (moss, ferns,...) so it would require less triming as it would become a chore later on, unless you intent to sell plants. Water change weekly should be ok depending on the bioload. For my 1 ft tank, I think should not have more than 5 fishes (my take) and since I have shrimps (algae clearing crew), there is limited fishes for me to buy. Might be able to hold more fishes but control your feeding (2-3 times a week, feed small amount) is a way to have slightly more fishes. Water change weekly should be fine (I do that for my tank for about 10% weekly).