Brake cleaner will just clean off the grease but won`t loosen the bolts.
Taking off the mount arms is one way to do it, then you will have the mount bolts right in fornt of you. it is a little more work to do. on the left side it will interfere with one of the power steering hose connections. removing it, better have a bucket to catch the ATF.
I removed mine when I was replacing the oil cooler lines, looked logical. did create some extra work with the ATF all leaking our and having to quickly get the pan to catch the oil.
I helped JIMMYJOE replace his mounts, think it took us 4 hrs to do the job. It`s a simple job, just a PITA to do. Just make sure to dig out the grime that is in the bolt so the hex fit all the way in or you have the chance of rounding out the hole.
I use a little anti sieze on the bolts, so next time it is a little easier. you guys in the salt belt, this should help.
All of us out here in the peanut gallery will be cheering you on
Charlie ☺
I just reread your first post, you want to cut off your bolts on the back side. I don`t understand how to do this if you can`t even get to the bolts in the first place to loosen them. those little bolts screw into the frame of the car. are you talking about on the bottom side? there are no nuts on the bottom side to cut off. and if you use thread locker on the bolts, it will just make it harder to remove next time.