If the plumbing both before and after the softener loop is 1", then it would be worthwhile to upgrade the softener loop to 1" pipe as well. If everything after the softener is also 3/4" pipe, then upgrading the softener to 1" won't buy you much. Also choose the Fleck 7000 for the softener IF you upgrade pipe sizes. Or even if you don't. It has larger internal ports, while 5600SXT is only 3/4". For maintenance and parts reasons, it can be convenient to choose the same valve for both the carbon filter and softener. 2.0 cu ft carbon is OK, might consider upgrading the softener to 2.0 cu ft for higher service flow rate and low salting options.
Check on your municipal supply, chlorine or chloramine? If it is chloramine use Centaur carbon for your backwashed filter. And definitely go with an RO for drinking water at the sink and fridge. Best to supply it with softened water.