Help with Starting a subcutaneous PCA

I hope these are not stupid questions but here goes hehe:

When starting a subcutaneous infusion, can you use both a regular IV catheter and the butterfly IV catheter?

At our facility we have both the BD Insyte Autoguard IV start catheter and the BD Safety Intima (butterfly). Keep in mind that we do not have a specific policy for subcutaneous infusions but only a broad infusion policy from our pharmacy. We have an end of life resident at our facility and we are having some difficulty controlling her pain (she is currently on fentanyl patch 175mcg and roxanol 1m qhour prn). The idea for SUBQ PCA came up and I want to have as much information as possible before we cross this bridge with the IDT.

My second question is that comes from the literature that I have read when priming a subcutaneous infusion. You cannot prime the Autoguard until you retract the needle and you cannot prime the Safety Intima until you unscrew and pull the needle with the safety device. How do you prime these sets with either IVF such as NS or morphine sulfate if you are doing SUBQ PCA infusions? Is it ok to have some air in the line prior to attaching the IV tubing with the Safety Intima butterfly catheter before starting the infusion?

I've started tons of peripheral IV's in frail and elderly residents. Is it more or less difficulty than that?

Thank you! Any information would be appreciated.