aquarium - i'd suggest something larger, but everyone has a budget and/or needs a place to start
substrate - playsand alone (if you want to go the extra mile look for some organic top soil to put under - i'd say some research as well so you know what you're walking into and nothing goes wrong, ... just saying. a place to start would be dianna walstad's book)
plants - hardy plants are java fern and anubias, ... otherwise, have fun. pay attention to leaf size, 10 gallons is a small tank. stem plants (if you search enough on the net) list leaf size, but don't stop growing, they only grow fast or slow)
lighting - 6500K, skip the cool blue or cool anything.
water - if you have an RO unit, just be aware it strips near everything from the water, including all the micronutrients your plants need & want. ... but it does remove the things you want out of there as well, so take the good with the bad, ... you can add needed minerals, but once in your tank it's hard to remove toxins - yay for R/O
fertilizers - i honestly don't know.
covering - custom cut glass sheet is my preference, lets in light, slows down water evaporation, keeps it's shape. there are hinged glass lids on the market - with a solid opaque plastic hinge the will block the light you want in your tank
snails - an eyesore to some, ... otherwise beneficial. eating excess food, so they keep ammonia/nitrates "lower" (think 3 instead of 4) malaysian trumpet snail dig, this is good. the also reproduce enough you think rats and rabbits are attending a monistary and have taken a vow of celebacy, ... IF you are overfeeding. otherwise i would recommend the assasin snail, they will keep other snail down/gone, they dig, they reproduce very slowly. win-win all around
water changes - you have plants, once your tank cycles, a nitrate test kit will tell you you don't have to do any water changes
air stone - something different
what do your fish want ?, fast water or slow water, or still water ?
-fast water, i would recommend this: River-Tank Manifold Design — Loaches Online
(will PM this part incase there is something here against advertising other forums)
-slow water, i would recommend a long bubble wand against one end of the tank. this will give just enough water current to keep a very slow gentle flow going (if you ever get hair algae you'll see it as the algae will bend to the water flow) any plants, and even stiffer algaes will resist showing any hints of water flow (so very slow gentle water flow)
-bettas i think are fine with no water flow, ... and the plants will take care of the rest of the O2/CO2 stuff.
other - i would recommend letting your tank cycle, unless you wish to follow diana walstads recommendations and steps (there are ways to speed this up - media from another established tank (prefered), waldstad method, adding fish food or pure ammonia (do some research first), when your ammonia/nitrite numbers are zero, your nitrates are good for plants (in moderation) - others may be more help - or a bunch of research