Is this something we should consider or am I looking too far into this? Im looking at doing trips from several days/weeks so thought it would be a clever safety feature
You can't prepare for everything. Cracks on newer Hobies are relatively rare, tend to occur in drivewells (if anywhere) and generally give adequate warning before they become significant problems.
I think Duct tape would temporarily seal or retard most cracks as long as you take the stress off. Try some on your hull and see how it works. If things get worse with your TI, you can abandon the drivewell (you'll still have a sail, one Drive and a paddle) and seal it from underneath. I do this often when soloing with the Oasis -- works great with packing tape:
If worst comes to worse, remember your TI amas each have 220 lb buoyancy.
Space being limited, I'd be more inclined to carry a few spare parts (and tape) than a welding kit.