Welcome & congratulations on your new additions, we hope to see you on here, and if you can post photos, we love photos.
My 2 girls were not from PP, but I did have them on the PP diet when I first got them because a friend of mine has 2 from PP and swore by them. I was also very confused about who to believe, but when she said hers were doing so well, I figured I'd get 2, mine were re-homes from CL, both about 1 yr old and were gotten from a MD breeder by original owners.
I started to look for more info on the little creatures, and since I had been confused by the mix info on-line, I was a little hesitant in the beginning to go on forums. But I did, and I'm glad I did. I was reading about diets and in doing so I caught on to a term "crackling fur", I didn't know what this meant, so delved deeper and found photos of soft, fluffy furred gliders and notices that my girls had crackling fur. I had to ask myself, was I providing the proper nutrition to my gliders, and farther researched.
What I can tell you from my personal experience.
Glider's don't like to play during the day, if they do wake up it is to only eat, potty, & maybe drink some water. This makes me feel sorry for PP gliders at the demonstrations in malls.
Adult gliders do not need additional heat source, it can contribute to drying out skin & coat. (If your temperature conditions where you live drop below the gliders lowest temp, below 70, you can use a red bulb in a lamp on a thermostat, to only come on when temp drops below 70 and will turn off once reaching 70 again, although there is still some debate). No heat rocks, they're bad even for lizards imo.
The diets are not necessarily that complicated or expensive, some varying degrees based on which diet, where you live (costs of ingredients & shipping where applicable), and how much you want to spend in treats. They may cost more that annual cost of PP pellets & apples, but reasonable still.
Recognized diets in the Gliderpedia will give you great options to choose from, check out the ingredients to determine you can have easy enough access to them. Also check out the mixing, prep, & serving instructions on them. It's important after you select a recognized diet (one used for years with results in healthy gliders) that you choose one you can stick to.
It's not that hard really, and varies in costs, but I feel most will be reasonable in cost. Try doing a search on this forum for "how much do you spend on your glider's diets" or "on feeding your glider" questions. My girls loved their PP pellets, so I use them as foraging treats, I hide them in their toys & hides, usually early morning, sometimes late evening after they've eaten most of their main diet.
I have the minimum size cage 32"w x 21"d x 36"h, bigger is better, my cage came with the girls and they seem happy in it, but if I had more space, I'd get at least a little taller one. The PP starter cage, imo, would make a fair travel cage or for hospital, temp, quarantine situations, I'd keep it.
The wheel you got is not safe, although some have had gliders on there with no mishaps, dangers are present, why chance it? I recommend getting one s/a Fast Track, Raptor, Custom Cruiser, Stealth, or Rapid Runner, check them all out. You do not need to throw out your wheel, when disabled & laying flat on cage floor, they make great play boxes.
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Bonding, takes time, patience, consistency, & treats are key. Glider's personalities vary, some will respond quicker than others, some may bond more deeper as well. It can be a roller coaster ride with ups & downs, you may make progress, then have setbacks. Just know if you have setbacks, you can just go back a few steps in the bonding technique or try some variations.
Please stick around, keep researching, look up photos, ask all questions you have, you will find this a knowledgeable community that is also fun and learn many things glider that will be helpful to you & your gliders.
Wish you the best of luck.