It is true that employers (in all 50 states) can stop PTO accruals on a go forward basis for any employee (regardless of how many hours they work) unless they have a legally binding and enforceable contract that guarantees them the accrual.
It is also true that an employer can make wage cuts, again on a go forward basis, subject to any notice period required by state law.
However, unless the 401(k) document expressly states that employer contributions are discretionary, in which case there will be specific circumstances listed as to when they are and are not made, they cannot stop making 401(k) contributions randomly. There are all KINDS of notices and administrative requirements before that can be done.

