what are the chances of adult bunnies getting adopted?

I've adopted fully grown rabbits many times before, even ones that are several years old, as long as they are healthy, I see no reason someone would not, heck, I'd adopt any rabbit in a heartbeat.

And even though people 'prefer' babies, fully grown rabbits generally have a better chance of surviving the winter right now, and some might not be as tamed as someone would like, any rabbit can be taught to be gentle. I've adopted two year old rabbits that have bitten me, scratched, all of that kind of stuff and now they are the sweetest things.

How old are the 2 you have now? Typically rabbits that appear to be bonded when young, may lose that bond when hormones kick in. Usually one needs to fix both rabbits in order to successfully bond them. Once you do have a bonded pair, then introducing a 3rd bunny can result in the breaking of the original bond.

The bottom line is that it is difficult to make rabbits get along. Only babies get along --- temporarily. Pair bondings can be done, depending on the personalities of the individual rabbits.

There are many advantages to adopting adult rabbits. But most people who adopt adult rabbits get them from rabbit rescues because they are sure to fix all of their rabbits. Fixing them makes them more consistent with potty training, removes hormonal issues, and makes them more willing to bond.

There is a page about bonding on my site:

http://rabbitsindoors.weebly.com/bonding-bunnies.h...

Elsewhere on the site are the advantages of adopting older, fixed rabbits. There are also litter training tips (since you mentioned that).