Happy to hear you're doing the work yourselves! Should be a great learning experience!
I've not seen authentic 'tune-o-matic' bridges collapse like that, they are very sturdy (an ABR-1 would be more likely to suffer than a tune-o-matic) Again, more likely to be a knock off made with softer metal. Heavier gauge strings do require more tension but that's assuming standard tuning. And how heavy is "heavy"?
I doubt if anyone would be seriously playing anything above 12 gauge on an electric, and if so, they've either got hands like Stevie Ray Vaughan, or more likely, they're playing heavy metal music which typically calls for drop tuning...lower, not higher tension. In any event, you'll be replacing the hardware so it should all be good. Just double check the string spacing matches on both parts.
Good luck, have fun, and don't forget pictures!