There is really no way to know. One male/one female or two males can be territorial and difficult to bond too, so there isn’t going to be any cut and dried rule of thumb. It really will depend on the rabbits involved.
It’s best to not go out and get 3 or 4 baby bunnies b/c there is just no telling what their personalities will be post-altering. Start with the two you have, bond them. Give it time for that bond to cement (AT LEAST 6 months, I’d suggest you wait one full year). After that time, take the pair bunny dating to a rescue with altered rabbits and allow them to pick which one would be a good match, might be male, might be female…
The people on this site who have successfully bonded a trio of rabbits, it has taken them months from start to finish. You need to bond each rabbit to the new bunny individually, and then try to get them to accept being all together. It’s very labor intensive. I personally would love to have a trio, but when in the presence of a third bunny, my bonded pair will fight EACH OTHER viciously. They don’t want a new guy/gal around.