Wow... that's a lot to identify at once
I'll give it a shot:
1. Standard US Army Airborne sidecap. The badge was used for many decades after the war. Very nice one too!
2. Commercial 6 color hat.
3. Genuine Marines 8 corner cover. I didn't know they were made 50/50 mix.
4. Genuine 3 color desert hat.
5. Marines side cap. I don't know enough about the dress uniform, but it likely is the same model now as decades past.
6. Not shown
7. RAAF for sure, not RAF. Apparently fairly recent issue:
8. Para berets are a speciality all on their own. It does appear to be a legit Brit para beret.
9. RAAF enlisted rank beret. See above link.
10. No idea. I don't know what the inside of a Vietnam issued OG-107 cap looks like. Many other nations used similar caps.
11. UK arctic mitten shells. No idea what the timeframe is on these. I have a set and have thought of them as 1990s issue.
12. Very interesting. There is a "Q" number and there is an "A" stamp, which indicates Bundeswehr. However, the date appears to be 1979 and I can't think of anything with this color that would be used by the BW at that date. Earlier they used dark gray sidecaps like this BUT they had piping on them. I'll see what I can find out about this.