Howdy fellow Michigan guy! Definitely check the condition of the strut towers and other locations on the underside for corrosion damage. I'm not suggesting all hope is gone if its rusty down there by any means, but you'll definitely want to know what you're up against as you dig back into your project.
As far as replacement parts, finding clean ones is tricky in Michigan. Unfortunately due to their resale value these vehicles have become largely disposable, and Michigan road conditions throughout the year don't help that up here. When I had my QX4 I frequently found useable parts at pick-and-pulls in the Grand Rapids area, they all have online inventories with pictures. Here's the 4 I've been to, it may be worth the drive if they've got the parts you need:
Weller Self Serve (it's not uncommon for these guys to have 1/2 off days):
https://www.wellerselfserve.com/
LKQ Holland:
https://www.lkqpickyourpart.com/locations/LKQ_Pick_Your_Part_-_Holland-346/recents/
LKQ Grand Rapids:
https://www.lkqpickyourpart.com/locations/LKQ_Pick_Your_Part_-_Grand_Rapids-348/recents/
Lucky's Self Serve (just opened this year):
https://luckyselfserve.com/
I'm in a Toyota now but I know a few Nissan guys in the state, if you ever want to go wheeling let me know!