Which states? That's a legit question these days. I live in Colorado, can I count on some of this stimulus? Maybe. If I lived in California, probably not.
Any state that wants a loan can get one. This isn't really a "stimulus" per se; the Fed is just ensuring that states facing short term liquidity issues can continue operating. To solve the broader structural problems at play, the government needs to step in with some fiscal stimulus.
Sure, and anybody who wants a covid-19 test can get one.
I haven't had time to read through the muni details but they are linked below. As far as I know, every city/state qualifies. There's just restrictions on pricing vs rating and size vs previous outstanding.