Great write up with good pix.

I had the same issue with a leaking Washer fluid tank on my Daughter's Pontiac.

I waited a few months for a backordered tank from the Pontiac Dealer, and finally gave up.

I ended up pulling the Tank, then hit the outside seam with nice shot of hot glue, waited for it to harden, and then reassembled.

It's been over five (5) years and it's holding strong.

This approach may be worth a shot for cost containment, before replacing the tank wholesale...