Hi Kathy,
So much depends on how early they picked them. Take the hibiscus for example. If you pick the pods just before they are about to open, almost all of the seeds will be viable. If you go back a few days before that, some will be ready and some won't, a few days before that and not many will be viable. The farther away you get from the cracking open stage, the less the seeds have a chance of being ripe. Also drying under ripe seed off the plant won't make them ripen, it will just make dry unripe seed.
You could ask how many seeds the trader is sending since extra seed would help make up for a lower germination rate.
Remy

Hi Remy! Long time no talk! I agree and that was my thought as well. I'm feeling more and more as though I would just rather give this trade a miss. I would rather that than to get upset because the seeds turned out not to be viable next spring. I'm just really thankful this person mentioned that they'd gathered the pods before the cracking open.

Kathy