Unfortunately I do not know anyone from SC.
Frozen fruits and veggies are ok (and you are aware that it does not to be salted or spiced in anyway, so that is good).
The pellets is better if you serve them as they are, without adding anything to them. Many agree that chewing on something hard, helps simulate the chewing they do on bark (in order to get to the sap) and also keeps their teeth clean.
With the fruits and veggies, they only thing you need to keep in mind is that the recommended Ca:P ratio is 2:1. Candy has a list of safe fruits and veggies that has the ratios for each, you may find it here:
www.gliderkids-diet.com/FruitVegLIST2011.pdf
As long as you are offering a wide variety of fruits and veggies, the ratios should balance out.
Frozen fruits and veggies can keep for a long time, they may loose some of the nutritional value, but is not something so significant that they won't be getting what they need. To help preserve these nutrients is better if you let them thaw instead of boiling the fruits and veggies. Don't worry, frozen veggies thaw fast, and gliders have no problem consuming it.
My gliders prefer veggies over fruits. They love okra, snap peas, parsley, and many other. Presentation does seem to impact their preferences (little brats
), so trying different presentations should help consuming more of their food.