Destroying the Al Aqsa Mosque would be certain from a nuke strike- the 3rd holiest shrine within Islam - would they do that- No is my opinion
Will Saudi look for a nuke- I would say the probability of this occurring is darn near 100 %.
How many countries have been invaded that have a nuke capability- none.
Iran has the tech now- it is how long it would take to assemble a weapon is where the talks are focused- How much lead time for the West to be able, if needed to use other options, including war.
Do I think negotiations if agreed upon will prevent them from doing this in secret- No- the only way would be open and immediate access to inspectors to any site in Iran. I do not see Iran accepting this.
Then the period of years for inspections.
This would need to be permanent. Iran will not accept that.
Taking out the nuke facilities only slows them. Then what?
As to supporting Hezbollah and others- that is a side issue - but having an Israel- PLO settlement of the borders and such would undercut Hezbollah-Hamas.
If not then the EU- US- Canada would need to list both as terror orgs. Stop all aid.
Quite the circle of problems.