Chasing some advice on this foil setup. Absolute noob to foils so any info would be appreciated ??

There is 1-2mm slop in the mast base plate connection. Its only very slight so I am wondering i should just try it and hope for the best. Or if it could be shimmed or fixed up in somehow.

Would a slight wobble in the connection be catastrophic for foiling.

The base plate looks solid as a rock. So it seems the movement is coming from the mast.

Should I just get a new mast and or base plate?

I'm no expert, but I try to avoid any movement at all in any of the joints. Movement causes wear, which leads to more movement, and also corrosion as the anodising is worn away. Also puts more stesses onto the screws.
Mast to base plate joint is subject to massive leverage forces, so we really don't want any movement there.
Photos are suggestive of small cracks in the mast between screw holes and mast cavity; if this is the case, mast could crack open and break loose. Could possibly be shortened slightly to eliminate any cracks, and re-tap screw holes as needed to give full depth of thread. (Or a new mast.)
If no cracks I'd try 'shimming' the loose joints to eliminate any movement. A bit of duct tape around the male part can be effective. And lubricate before assembly; eg: smear of Tefgel. Which also helps protect against future corrosion, and should be applied to all joints and screws. (That white powdery stuff you can see is caused by corrosion.)
Enjoy your foiling journey!