This would be wage theft. You can file a complaint with BOLI, or find an employment attorney in your area to go after them.

Yes they can. Absent a specific contract for a specific term and amount (and this does not sound like that), and employer can prospectively change...

This is the applicable law: https://oregon.public.law/statutes/ors_87.689 They have to send a notice first, and it has to give at least 30 days.

No on making you pay the difference. The missing paycheck is a bit more nuanced, but long term they owe you the money. Not to mention, as soon as...

You can try a public records request, but typically the DA will refuse to turn it over if there is an active criminal case.

Hire a landlord-tenant attorney to look at options for ejectment or eviction.

Mostly likely not, as you had your one bite at the apple. Unless this is a completely new issue, you can't sue again.

Unless you have injuries that need medical care, unlikely you would get much of anything in compensation, more likely a refund.

Any personal injury attorney can help your friend, but your friend ultimately is the one who has to want the attorney.

There is a statute that prohibits what you want to do. There is an exception for small claims court, but it is a very narrow one.