I have no clue on the "cup cakes" - are they very hard, intended to help wear down the rodent's growing front teeth? If so, they probably are not a good choice for sugar gliders.
Gliders teeth do not continue to grow and a very hard treat might cause injury.
The berry treats for rabbits are probably fine - but too big to offer a sugar glider as a treat. Cut them in quarters and offer smaller pieces in limited amounts daily.
Remember treats are just that - something you can offer 2 or 3 daily so that your glider will not fill up on the treats and then not eat the food needed each night for the nutrients they need.
You can always use a piece of fruit that would otherwise be included in their dinner as a treat during the day time or during evening out of cage play time. That will not spoil their dinner.