I don't know that much about jets, but reading articles about fighter jets theyalways seem to need dozens of maintenance hours per flight hour.
That's pretty much the case with any modern weapons system/platform - hence part of the reason for the delays in getting modern western equipment into service with Ukraine.
This means a lot of parts to replace, I assume. Are these parts still around in enough quantity?
again, part of the reason for the delays - one needs to make sure the sustainment support system is in place. In the case of the theoretical Tornados here they are still in service with Germany, Italy and Saudi arabia so presumably there are still spares etc available. I am not sure what happened with the RAF stocks when their aircraft were retired but some of that may still be available.
It means a lot of people have to be trained, From what I understand they will have to be untrained first.
Again, something well understood and part of the reason for the delays. That said, in the case of other platforms (not the theoretical Tornados obviously) there is training underway.
I read an article somewhere, I forgot where, about former WARPAC pilots going to NATO jets. Apparently it requires a completely different mindset. Also, Tornados essentially attack aircraft.
Not as much as one would make out. Moreover Ukrainian forces have proven themselves quite capable of taking on other Western systems.
If this war has taught ujs one thing its that ammunition gets burned through at incredible level. Are there enough bombs and rockets and drop tanks to support open ended high intensity peer to peer combat?
Indeed this is the case and one that is being addressed already despite the best efforts of some to undermine the efforts.
What about tires and brakes and god knows what else? Also are there a lot of electronics and the like that shouldn't fall into Russian hands?
Ditto above comments re sustainment systems.. In the case of the Tornados the fear of falling into Russian hands would be less of a worry.
It might be easier, cheaper, and quicker to scrounge MiGs and Sus from former WarPac nations in a swap for mothballed western jets.
They have done that already but these are getting harder to find.