Yeah the starters off. There's one thread I can get with a pair of vice grips after I get at it with a some heat. The second one I'm gonna have issues with.
I do not have luck with welding bolts, so heat the bolt, touch a candle on the threads, and use REAL vice grips on the longer stud. Avoid the fake tools.
Then, file a flat top on the remaining bolt, center punch it, use a left hand drill bit to drill the right size policy hole, heat, cool and use an easy out will be the least destructive way on a short piece. Tap the bolts while hot to loosten the rust. Pray and offer sacrifices to your supreme being while waiting.
When it all hoes badly, drill out the old bolt, tap for a helpful, and loc tight (darn spell check!) The new insert in.
The Aerospace industry has a cool way to zap out stuck bolts like a ray gun. I first saw it in Hot Rod in the last year. It is too probably too expensive for your application, but a real Boss model block and expensive scatter shield might be worth it.