Either of those plants would work. Personally I'd suggest leaving the top open when and if you can for air circulation, but not everyone thinks that's necessary obviously.

I'd put the plants in the peat. Or if you go the potted route, maybe repot them into a pot with peat. That would prevent chemical fertilizer from leaching out or nematodes in the soil from breeding.

Any of those plants would work! You may need to rinse them off very thoroughly before adding to the tank. Removing dirt from the roots and all and maybe quickly rinsing with a water and tiny bit of bleach solution. those species in general are pretty tough.