I am unsure this is a bug, but it is both confirmed by Sponduli and Magister, so it might warrant looking into. The DC versus poison save is there, and if PfE stops it, it means it's a bug.
Not a bug because it's a paralysis which mind spell immunity protects against
Paralysis is not mind effecting tinker tom. Only the spells Hold Person and Hold Monster which cause paralysis are considered mind effecting spells, all other sources of paralysis are covered only by "immunity to paralysis"
I don't recall PFE blocking this at all, but if it does I suppose it's a bug and the creature should be BUFFED to fix it. However, their AB might be a bit high if this is buffed.
If this is fixed, then the complaints raised against these creatures in the Suggestions thread are again valid. (Let's not start that discussion here by the way! I'm just pointing out that this'd remove one of the checks against this thing being overpowered.)
No, paralysis is mind-affecting. It just never worked with the old creeping vines since they weren't evil! H'bala's creeping vines are on the other hand. Possible to fix, but the effort entailed wouldn't be justifiable.
As Johannes clarified, paralysis is indeed mind-affecting.
What's different (because it's scripted differently here in efu) is that Hold Person/Monster is now up against mind-affecting saves instead of raw will saves (so the saves accumulate if you wear items with both +1 will and +1 mind affecting). All other paralysis spells are up against Will saves and not against mind-affecting saves.
[Edit: or yeah, fortitude saves]
The save here checks against Fortitude and Poison saves, not mind effecting and will.
But yes, Not worth the effort entailed. Creeping Vines aren't that scary though, if you aren't going to pop a fortitude potion when you go explore withered lands, you deserve what you get for being cheap!