Come up with the most minimalist setup

[beersk]

I think you could put a couple weights (dumbells) on the top of the kettle. I don't think you have to worry about "bugs" crawling in, unless there's a draft.
I recently fermented a hefe in the brew kettle that turned out pretty good. First 3 days in the kettle, stirred once or twice, then transferred to a secondary keg with airlock (gas post blowoff hose). It was at 1.017 when I transferred, and finished at 1.011. I liked the process. I'd like to be able to do that for all beers, but I do brew lagers and I don't think it'd be a good idea to ferment in a kettle for a lager...but perhaps I'll try it sometime just for kicks, maybe just give it a little longer in primary.

 

[shoreman]

Interesting, I have some spring clamps and will tryout.

 

[Weezy]

No reason to be so ocd about sealing the lid. The intent is to keep floaties in the air from drifting into the beer and bringing wild yeast and bacteria with it. It's not that you shouldn't button up a lid but just keep in mind the true purpose.