You are right.
Locks will be changed. Checking accounts will be moved to another bank. Hubby will be power of attorney.
The other important thing is to get that POA while your MIL is able to give her consent. If you wait until she's incapable, it's much more troublesome to get.
AND since your on the POA thing...how about the Living Will or POA for Health care decisions? MIght as well as have that done too.