@melvin-fox Appreciate the encouragement.
I've had to reconsider the design and features of the enclosure as I was relying on somebody else to build it and now am unsure on when or if this will happen anytime soon. Using an arcade stick with the Pi was the priority so for now, the Pi will stay as is and outside the initial build (version 1). I'll continue to power it as I always have.
As this is my first arcade stick build and likely to be a temporary solution, it's very low budget. It's currently housed in an cardboard box! I'll look into upgrading it into something more classy once I can establish how much use it's going to get. I received all the parts last week and spent some time on weekend wiring everything up to ensure it was all working.
I'll reconsider the options we discussed here once it's upgraded and decide if an all in one arcade stick/PI solution is the better option. More importantly, if it can be achieved using the few tools I have access to whilst keeping costs to a minimum.