Evening Murph. First off let me wish you good luck and hope you enjoy your time with your 135. Hopefully you're not in a hurry so you can take your time with it.
For your fender bolts, I don't know if you have a compressor or not but when I don't want to use heat I have a pneumatic chisel that I've made an extension for that allows me to impact seized bolts. I've had pretty good luck after soaking them with an anti-seize for a day or two. I've had my fenders off a few times, there is room for the tool.
If not I'd continue on the way you're approaching it, keep them soaking in anti-seize and give them a wack every now and then, perseverence is key, "we shall persevere for we are strong and they are weak"................