We aren't that hot, but mid 90's with dew points in the high 70's melts us further north. My old garage is detached and is semi insulated so it is not too terrible for much of the day, as long as the big door isn't open.
No support under the transaxle. The rear passengers corner of the engine is actually supported by a bracket on the trans so the only actually motor mount that gets disconnected is at the passengers front corner under the A/C compressor. I hope to leave the oil filter adapter from the S/C engine in place, the one that curls under the front of the oil pan, but I won't know for certain until I get the oil cooler adapter back in place. I had to remove the oil pressure sender along with the aforementioned items to better access the rear mounts and the hidden bellhousing bolt. I didn't think to take a photo before I removed it but I will when I reinstall. The reason I mention it is the different orientation from the standard LN3 location. It points straight back rather than vertical but I didn't realize how low it was until engine installation. It is only about 1" above the inner drive axle joint. That shouldn't be an issue as they don't move relative to each other, but it was a bit of a surprise.