Is there some way to get a bunch of statics to snap to grid/angle at once? I notice that if you copy a collection of items they don't automatically go to grid, so if you're copying a large interior or something you need to dismantle the copied version and put it back together for it to fit on the grid if you want to make modifications to it. It's sorta tedious.

I don't think so. Selected groups act as one object, so they Snap along the same direction or angle. (as opposed to snapping into one solid)

I do wish there was a "snap all selected to new grid solid object thing" button sometimes... especially in the situation you describe.
Ever try copy/pasting from a different interior? Sometimes the pasted grid refuses to ever match what you already have, and unlocking the grid is the only way to get them to match.
(or is that what you described?)

Yeah, I've run into that too. Creating decent interiors is definitely extremely time-consuming (for me anyway), so I wish there were a few more shortcuts.