1995 E350 cat converter loose

[jonesg]

95 E350 van, the exhaust is loud,
the flange joint ( looks like this -][- )
in front of the cat has 3 nuts broken off, tried to knock the bolts out but I think they must be welded studs? The only one left holding it together is on the top, I could cut/grind that off easy enough and drop the front section, could I then drill out the studs and replace with stainless nuts/bolts ?

The cat is still good and I don't want to pay for a new one if the mounting can be fixed on the old one.

I don't have any way of getting the cat seperated from the rest of the system so I'll have to do everything under the van (the tailpipe goes over the axle) . unless...

Is it possible to hacksaw thru the pipe behind the cat, fix the broken studs (drill em out on the workbench) and then reconnect the exhaust pipe again with a slightly oversize pipe and clamps?
I need to get this done as inspection is coming up in 2 weeks.

The exhaust system looks fine otherwise.