While supplemental co2 will benefit all plants, it really isn't needed by any that can thrive in 2 wpg or less.
If you plan to use substrate and plant in it, you will need to have some mulm build up and to use substrate ferts at the outset. If its an all plant tank, then dosing will be more complex because the macro nutrients typically supplied by fish and excess fish food waste etc. that supply these things will be absent. You will need to add them and likely nitrate as well.
Some plants will need more care than others. I typically have a bin for excess plants- its water and plants- ferns and anubias will do great in it for months on end, stem plants can be floated and all but the most demanding can last for some time. Anything from the high tech plant world won't last long in the bin however. Rooted plants like swords can not be floated for any extended period either.
