Any question answered...

I've just bought some 1" ones for 1" forks. However, they're a bit loose. I'm sure all my 1 1/8" ones have always been snug.

Any risks?

No

Also the bottom of the headtube where the bottom headset cup sits seems to be a bit big, so the bottom cup moves around a bit. Is there anything I can do about this?

Not really, without a lot of expense. Chris King do oversized cups for head tubes which are worn or over-reamed, but I've not seen any from any other maker.