As you become more experienced, you find more and more situations where would can take even multi row pan entirely hand held and avoid parallax.
But this is rarely the case for those new to pans as stitching errors and failed pans blight many of their attempts.
Unless I am going out to take pans I will not even take a bracket with me. But they are good to keep in the car just in case.
1. Such a wide fisheye will lose a lot of resolution. You can partly compensate with 60mp sensor but really not what I would do. Something like 20mm will take many more shots but details will be on the next level
2. You can be careless with plain sky and simple grass but this is not the case at all in real estate. Fancy ceiling and mosaic floor. You can't be taking chances with that
3. Ptgui is expensive and completely unnecessary. Hugin is where it is really at
Post is really not a problem if setup was correct
Even on my Fuji XE2 the raw file size from the Samyang fish eye is far larger than necessary and needs to be down sized for a usable 36x180 VR web display
It produces a sharp and detailed image.
I use The much less expensive PTAssembler for single row and multi row pans hugin works but is far more of a hassel and less convenient when needing stitching adjustments and patching.
However nothing at all matches the versatility and speed of use of PTGui the difference is night and day. However it is aimed a professionals who can cover it's cost, in time savings and quality of output, within a few shoots. The pro 13 version In the UK it is now about £360.00 Including vat. An upgrade to it is about £180 which is all more costly than most amateurs could justify.
If you have a trial version you will have a copyright stamp all over the output. If you were to ask a friend a to output the worked up files on their paid for version it is a winner. And as far as I know not illegal. However you can not share the program on your computer.
As a 90 year old retired photographer I can no longer justify using it.
If I was still a working photographer I would no hesitate to have the latest pro version.
A vat registered photographer can of course recover the vat
The non pro version is not worth the money as it is totally defunctioned..