"will" use? As in...
"Will" as in "when tourists are populated" (i.e. when you create a neighborhood).
i.e. should I bother testing for this group to make sure that I also include this group as potential "townie"/NPC types?
What is the difference between "actual tourists" and tourists (0x7FF4)?
And why are there two groups (ox7FE5 and 0x7FF0)? Is there any difference between them?
0x7FE5 is the first group, and 0x7FF0 is the last group. As I said, this is a range. In other words, them and every Id between them is used for Tourists.
It's currently unknown what use the 0x7FF4 Id has. I suspect it was "pre-deprecated" (as Microsoft is wont to do). In other words, they suddenly decided to stop using it.
Tourists are essentially the same as townies. The only real difference is that they only appear in "Vacation" sub-hoods, and that they generally appear as a group. There are always 4 sims per familyId, all with the same family name, etc.
Whether you should test for them really depends on the purpose of your code.