Rotary encoder with DT interrupts

[richard]

no, 5v all the way unless the app calls for 3v3 (typically when I use a Nokia GLCD). In any case the PIC should be able to handle 3v3 at low speeds, surely?

not sure , for the 16f1788 the microchip ipe with pk4 warns , 5.00 v recommended (not sure where the ldo comes into play)

I make unused pins output so don't need to worry about pullups as you would with inputs (else floating nightmares). I guess your wpu's take care of your inputs.

as i don't , i have never seen or heard of a pic having an adverse effect from an unused floating input. if your program is affected by an unused input then its incomplete.
the only measurable effect is a slight increase in power consumption (you need a microamp meter to detect it). floating pin nightmares for pic chips are a myth based on other logic families with fixed i/p pin to o/p pin relationships where totem-pole outputs could be driven at prodigious rates unnecessarily to bad effect, pics are not like that.
when breadboarding all unused pins set as i/p is a good thing, you won't damage anything with misplaced connections.