good morning n congrats
It doesn't really matter what they are "used to" or what they behave like with the current owners. All of that is about to change for them, which will probably change their behavior as well.
They are about to have a new human/humans, home, envirement, routine, smells, sounds, lights, food, bonding routine etc... everything is about to change for them so how they acted at the current owners house may NOT be how they act with you.
So don't worry to much about their past, look at is as a new begining for them because that is exactly what it is.
The big thing is to not have any expectations of them, good or bad. Just get to know them and learn who they are as individuals and let them get to know you and your family.
Make a routine, owning gliders is much like raising toddlers they thrive on routine and learn the routine quickly. Example bonding bag time, same time everyday, they will get to know it's time for hanging out with mom. Treat time same time every day, dinner served same time every day....etc. They will get used to the rythm of your daily routine.
You don't need gloves, bonding time should be during the day when they are the most docile. They should also be in their sleeping pouch so it's easy to get them out of the cage ( take the whole pouch out with them in it), might be hard to get them back IN the cage when your done tho
If your using a bonding bag it's easiest to just unzip the bonding bag n put the whole thing in the cage when they come out of it n go to their normal sleep pouch or whatever remove the bonding bag.
Most gliders don't like being picked up and held in hands, they have 4 feet and like to use them.
Pleaseeeee don't use hamster balls. 1 they are not safe for gliders, their nails can get stuck in the little slits on the ball. 2 They do nothing to help with bonding.
There are floor toys made specifically for gliders that are safe if you must have one but personally I think they are unnecessary for what they are intended for, however they are great for transporting gliders on short trips.
All you need is either a bathroom (glider proofed) or a tent for out of cage time. You want a small confined space to let them explore you on their own terms. Again during the day which makes it easier to get them back in the cage, usually if you offer an open pouch the gliders will want to go in it on their own especially if you turn the light on when tent time is done.
Most gliders aren't "aggressive" to humans, they are scared. Yes intact males CAN be aggressive but usually to each other over breeding rights or dominance. If they are intact and aggressive to each other get them neutered it will settle them both down usually within a month when their hormone levels decrease.
"bonding" with any age glider male or female is ALWAYS possible. Bonding is nothing more than learning each other, respecting each other, learning to trust each other. If something your doing results in a negative reaction from the glider, try doing that thing in a different way until you find the way that works for that glider. Every glider is different and may need handled differently.
In one cage I have 3 gliders, that all need handled differently. Nicky needs to be aproached from behind she absolutley can't stand hands in her face unless your giving her food, she will bite. She does not want picked up, she wants to come onto me with her own feet and find her own spot on me ( so I let her ). Cozig, i can reach in the pouch anytime and pick her up, twist her up like a pretzel she just doesn't care what I do to her, but god forbid anyone else try to pick her up or hold her. Hansel isn't a fan of being held either but if picked up he's ok he really wants to be a love bug underneath his false brovado. He's come a long way and is still progressing and evolving as all of them are. Learn each gliders likes and dislikes, you will figure out what works for each one, just don't get frustrated.
There is no "end" to bonding really, the bond continues to grow and evolve as long as you own them or they own you rather.