I think 2 rams would be okay in a 10 gallon along with say 3-5 guppies, and 2 ottos or 2 cories. As for tetras, I believe you'll be okay with any kind, its a matter of personal choice. The rams are the limiting factor b/c they require the most space.
In terms of plants, you can read around and find out the basics requirements to grow plants, such as lighting, fertilzers, co2, etc. But to give you an idea, for a low tech setup. Low light plants like java fern, java moss, anubias will do fine with just under between 2.0 wpg (watts per gallon). DIY co2 or Flourish excel will provide co2 and help them do better. As for fertilizers, flourish and flourish iron will help you, or go to Gregwatson.com and purchase some NPK and plantex for a year worths supply for under $20.
If you have more light above 2 wpg, then you'll need co2, and fertilizers.
Oh ya, 10 gallon is not too small to run co2.
If you desire more specific answers, and advice, how many watts are you running, DIY co2, fertilizers?
Best of Luck!