you'll be fine with 3/4 " in the partial panel but the trim cap would look nicer but you'll lose interior space.

REP2496 or REP 1 1/2". Check with the specks of the Frig as well to make sure it doesn't need any more than that sometimes they do depending on the way the Frig door opens.

The before mentioned are the ones we use the most.

Also what is the filler width to the right of the pantry?

I would use a filler at least 1 1/2" width so the door and the hardware do not hit the wall on the right. Most cabinet profiles used today are full overlay; and do need some cushion when installed up against a wall.

I would stick with the 30" unless you are in need of a broom closet etc. Once you split the cabinets there is a lot of wasted space in terms of the wood frame etc that will eat up on your storage space. I would do at least 2 pull outs for the bottom so the items are easily accessible and you are not having to bend to find what is hidden in the back.

Also consider if you are a Costco, Sam's, BJ's shopper. Many of the items they sell there are oversized and may need adjustable shelves instead of fixed pull out drawers. Cereal boxes also would need adjustable shelves. All depends on how you are intending to use that section of the kitchen.

In that case it is a toss up.