I'm a fan of taking in rehome gliders but it doesn't come without it's risks, and great rewards.
The risks are:
unseen vet bills if the gliders aren't as healthy as the owner claims.
Cage and accessories usually need replaced ( which you already have )
Behavior issues from lack of stimulating toys and or lack of being handled enough.
Most males aren't usually neutered, if your getting 2 girls that's no issue.
Unforeseen vet bills is probably going to be your biggest concern though. I would want to go have a look at them before committing to buying them.
Make sure their eyes are clear and bright, their nails look healthy they maybe long from lack of regular nail trimmings and that will need addressed pronto.
Make sure their nose is dry and pink, but nose might look purple if they have just woken up that is normal it should go to pink once their awake.
No lumps or bumps around the jaw line and mouth. Tail should be thick and plush, fur should be grey not brown but brown fur can be addressed with a good diet and will usually return to grey after getting them off pellet foods.
The rewards are watching the transformation from a neglected glider to a well bonded happy glider. Every milestone is celebrated even if it's something minor it is a victory. Being part of giving gliders a second chance and an environment they can thrive in is a wonderful thing, having the gliders accept you as part of their colony is an honor.
Many of us here have taken in a rehomed glider and are willing to offer help and advice for issues you may encounter.
I will say that if you don't feel you can provide the care and extra time they may need then stick with the breeder. There are far to many gliders that get "tried out" just to realize it's to much for them and they want a joey instead.
These poor gliders end up in a continuous circle of being recycled. If you are going to get rehomed gliders be committed to them and make sure your home is going to be their LAST home their forever home no matter what!
There is no shame in realizing it maybe to much of a challenge BEFORE you get them rather than after you got them. Your the only one that can determine if they may be a fit for you and your family or if you'd be better off waiting on the breeder.