It's plastic, but I don't consider it flimsy.
I do not believe Home Depot sells parts individually. Contact the manufacturer is what I would recommend. (Not verified by Home Depot)
Made in China. Yes comes with connectors
That shouldn’t be a problem.. there is enough space with the dimensions that you mentioned...we are very pleased
Hello Bernie, Pack Size here is a reference to product bundles. Some toilet models are offered in bundle quantities of 3 or 9 with special pricing for contractors.
Seat height is fine. But as far stains, I call BS. My black toilet from day one has had white residue, stain, streaks in the bowl. Nothing stops them from happening.
Yes you will need to purchase a connector hose.