Definitely regardless of the pairing, spaying/neutering bothbunnies (in my opinion) is a must. Just makes for happeir and healthier bunnies.In some special casesintact bunnies get along, but I personally rather not deal with the hormonal and territorial mess that comes along with intact bunnies and bonding!
I've found male/females generally 'click' better. Though try telling that to my stubborn Pebbles/Georgie.. so there are exceptions to the rule! If you spay the girls, they can get along great! My two females (Poppy and Jasmine)out of my trio are best friends, they are always cuddled with each other. Now if I tried to bond them while they were still intact, they would not have worked by any means. Poppy was just way too territorial due to hormones with other females.
Females spray too.. so it's not just males! Before I got Pebbles spayed, I would find spray marks 3 feet up the wall from where her cage was! (talented bunnies!)
So if I was you, I would spay Abby (if she hasn't been already)and then possibly check out to see if rabbit rescues/shelters do 'speed dating' or bunny bonding at the shelter. It's a great opportunity to see how Abby interacts with others and to see who or what type of bunny she clicks with.