I expect refurbishment usually occurs when a machine exhibits specific problems. I suspect the facility would replace any parts diagnosed as problematic, calibrate the unit and run some standard test prints to qualify the printer. There are some checks Support can do remotely from your logs (e.g. galvo power logs).
I once received a refurbished unit from Formlabs that had wet resin on the surfaces inside the main chamber and pooled in the honeycomb cavities of the baseplate, so I wouldn’t put too much stock into any illusion it involves a thorough disassembly and rebuild of the whole machine.
It sounds like what you’re asking about is more along the lines of preventative maintenance.
As you’ve identified, cleaning is probably the most common one. Not so much to prevent damage to the hardware (over-cleaning the first surface mirror or galvos could theoretically cause damage), as to keep your optical path clear and producing consistent quality prints.
Lead screw lubrication is another good one you’ve identified. Here’s some info I have on file for that: https://drive.google.com/file/d/0B-Rpx1ySV3QVR202elJld3FNNVk/view
You could also check the belt which moves the tank back and forth for any wear.
While you’re in that area of the printer, clean out any overflowed resin from the catchment reservoir.
You can also do a calibration print and update your X/Y and Z fine tuning.
That’s all I thought of from the top of my head. If the Form 2 behaves like my Form 1+ did, what might get you in the end is degrading laser power, and AFAIK there isn’t much you can do about that.