I'll break out specific component details into build instructions and project logs. This sections will cover the current status and overall design.
For now, as I haven't built anything yet, it's a ramble.
I've learned not to over-think things when ordering hardware from China so my initial purchases did not have a lot of prior research.
The base system is the EleksMaker® EleksLaser-A3 Pro 2500mW Laser Engraving Machine currently on sale at banggood.com for $190. There is a version without the laser for $40 less, and the laser itself is $120. Seeing this bargain price triggered me to finally actually do this. Getting it with the laser means that if I don't get the PNP working (or useful) I still have a laser engraver to play with.
As this only comes with a 2-axis controller I also ordered the Geekcreit® CNC Shield UNO R3 Board 4xA4988 Driver Kit for $12. This is an Arduino R3 clone (probably not with the Atmega64u serial) and what appears to be a clone of the Protoneer 3.00 shield. This electronics is probably a stop gap.