Will Amfleet IIs be added to regionls with the addition of new Viewliners?

Amfleet II coaches as first/business class and Amfleet II café cars as Bistro cars on the day services like Palmetto or Carloinian?

No.

…because the Viewliners are mostly baggage cars and a handful of sleepers. The Amfleet II coaches continue on in their existing service.

The reasons are simple. Even though Amfleet-2s are younger they have any where from 50% to twice as much mileage as -1s because they are on the LD trains. Even so there are not enough -2s to always cover all the LD trains so -1s are used at times on some LD trains.
This is all covered in the fleet strategy plan and budget plan for 2014 in Amtrak reports and documents.
Only a suspicion but if any Viewliner-2 coaches are ever built the excess Amfleet 2s may go to back up NEC trains as the V-2 coaches would probably go on LD trains. As a business class car ? no too many miles. .

Mileage is only meaningful to the running gear - which is easy to rebuild back to spec.