So discovered that one front caliper of my fiance's 99 Max was completely seized and the brake pads were down to bare metal!

I swapped it out with an re-manufacture caliper with bracket.
The new calipers came with a copper crush washer, I placed it between the caliper member and bolt. Not sure if thats right, but after cleaning the area with brake cleaner, I didn't notice any leaks.

Just after driving a bit, I noticed brake fluid spots on my rims.

Do you see any leaking anywhere right now? The spots may have happened during the repairs and you didn't notice them at the time. Clean the rim and drive the car and re-check.