Hi Mea,

Sorry to be a bummer, but trades should be of somewhat equally desirable plants. Folks won't be trading you a Hoya curtissi for a Pothos, as Pothos is common, readily available & cheap, a H curtissi is none of those things & you may have go to a nursery (or try Home Depot in Spring, I've seen them there maybe once).

You could trade a Marble Pothos for a regular (green) one. I don't have any suggestions for the other 2 plants, sorry.

I just picked up a bunch of plants at a garden show, another option would be to join a plant club/society. Also, my neighbour was able to find the plant she wanted online, on a craigslist like site.