May not match color and may not be compatible with your grout. Have contractor fix it.
Yes. Until the next freeze where the failure to drain the hose bib would crack the fill area, once again. In order to prevent damage from a sudden leak, where vibrations might be present, it would be safer to have the damage bib replaced.
That should work just fine. Just ensure the void is clean, grease-free and dry.
Get it welded.
I checked packaging, couldn't find if solvent-free or not.
Yes. I suggest adding a wood dowel 3/4" - 2" in co-located drilled recesses to add extra strength and rigiddity to repair.
not a chance
No. Engine vibration will cause the fill area to fail. May I suggest a standard marine fill-patch consisting of shredded fiberglass or fiberglass pad material and marine epoxy. Finish-sanding and paint, after 24 hours of set-time, will result in a better and more permanent repair.
Probably not, it may be time for replacement handle or new recliner. Did you know that Home Depot sells recliners too.