Have you set the ADCON1 to 0x0F. = All Port A Digital.
ref:
https://ww1.microchip.com/downloads/en/DeviceDoc/39631a.pdf
Page 105.
The other PORTA pins are multiplexed with analog
inputs, the analog VREF+ and VREF- inputs and the comparator
voltage reference output. The operation of pins
RA3:RA0 and RA5 as A/D converter inputs is selected
by clearing or setting the control bits in the ADCON1
register (A/D Control Register 1).
Pins RA0 through RA5 may also be used as comparator
inputs or outputs by setting the appropriate bits in the
CMCON register. To use RA3:RA0 as digital inputs, it is
also necessary to turn off the comparators.
The RA4/T0CKI/C1OUT pin is a Schmitt Trigger input.
All other PORTA pins have TTL input levels and full
CMOS output drivers.
I would personally use the display in 4Bit mode and move all the data and control lines on to Port D.
I have attached my last working LCD Code, its for the HiTech Com.
Hope this helps.
Regards
Ian