Is new without a delete acceptable?
Sure. Using new or malloc to set things up initially is really no different to static allocations. There is nothing inherently bad with using malloc or new, only in using it repeatedly with free or delete.

Allocating a block of heap memory and keeping it allocated for the rest of eternity does not cause heap fragmentation. It's only repeated allocation and deallocation of variable sizes (such as String causes) that start to create problems. Allocating at the start of your program and leaving it allocated, as long as you don't allocate too much, of course, is not a problem.