The first thing you should do is take both your gliders to a vet for a check up. You don't know the exact living conditions of your new glider. Before introducing a new glider it is recommended to do a 30 day quarantine. Gliders can get parasites so you need to make sure the new glider doesn't infect your glider. The process is called a fecal float/smear. They check the stool once then again in 30 days. If your glider gets a clean bill of health then you can begin the introduction process.
But you've already introduced them so, just make sure both gliders are healthy.
Usually gliders don't become friends right away. You need to keep them in separate cages and swap their pouches and toys over time. That will get them used to each other's scent. Then during the day when they are tired. Take them to a neutral area. Most people use a bathtub, and put the gliders together. Hopefully they will be nice to each other and want to sleep in the same pouch.
But your gliders have already met. So for now keep a close eye out for them to make sure they don't fight. Just be aware there are cases of gliders not getting along no matter what you do. These cases are few and far between but just be aware of it.
As for your diet, the BML is good but you need to also give them the recommended fruit and veggies, every night. That diet is high in calcium I believe and you need fruits and veggies high in phosphorus to balance it out.
I don't know the exact fruits and veggies but I do know they get corn and peas.
Also try varying the fruit, gliders will get sick of getting the same produce every day. Try fresh papaya, cantaloupe, watermelon, mango, peaches, plums, etc. (no citrus fruit and dried fruit should only be a treat)
Do some research on this website, it will give you the list of produce you should give your glider while on bml. You can also find a list of names to choose from for your gliders too.
Your new glider should be happy with a new buddy and should like the new food, give her a couple days to adjust, she might not eat well at first, don't worry about it, she should come around.