I didn't contribute with anything?
I already provided you a link to notebookcheck, which has a database of results for different laptops and told you what to check out.
You just had to look for laptops with
7940HS vs
7745HX which had at least 80W PL1 and compare them.
If you feared that RAM speed or timings will make a big difference between desktop vs mobile, then you only needed to apply the difference between Phoenix vs Dragon Range(Raphael) to a desktop one like R7 7700 or R7 7700X and you would have your answers.
You won't find more accurate results than this unless you wait for the release date.
From these questions of yours:
1. ST performance difference?
2. MT performance difference?
3. Power consumption & perf/watt difference?
4. iGPU performance difference?
7. Other differences?
Would be pretty accurately answered, If you bothered to check out those mobile chips at notebookcheck.
Only these are left ->
5. Idle power consumption difference?
Idle should be lower, by how much is questionable, but I don't understand why It should matter for a desktop chip.
6. Price difference?
No one will tell you how much It will cost, because no one knows It.