You can do to your threat whatever you please
That's correct there on the Oto's, they pref living in groups, also they're super sensitive fish, so don't introduce them to new set ups, ideally wait a few months till the tank is more established before adding them.
That's a myth many people fall for: You're tank will be much more vulnerable to have certain algae develop without plant then if you'd have plants.
Plants are like a bio filter inside your tank. Part of the nutrition they feed off of is the fish waste; that said if you don't have plants absorbing the bad stuff - Algae will develop on your decor and rocks.
Since you're redoing your hood anyway right now, while you're at the Home store (LOwes, Homedepot what ever have you) buy bulbs that fir the sockets you have, look for GE, Phillips, Bright effects manufactures and their "Daylight" bulbs, they're full spectrum and rated between 5-6500 kelvin. These bulbs are perfect for growing plants (that's what's over ALL my tanks and has for year on end now).
With that then in place, a fine substrate (play sand, pool sand or fine gravel) and some fish to come, there's nothing standing in the way of a nicely planted tank
Many think you need special substrate or ferts or CO2 systems to even think about plants - All tank you see under my aquarium log here to the left under my name are set up without all of that and the plants speak for themselves.
Now it is to add that some plants work better then others in small tanks, simply because of the size they grow to be. And then there's plants like Java Fern or Anubias that prefer being attached to rocks or driftwood and NOT buried in the gravel
That all said...you can order plants here if you don't have a local supply Sweet Aquatics
Any more questions pleaseee hit me with them - I love it when I can get people to go for planted tanks, cause really its much easier then you'd think at first
and soo much more natural looking IMO