Ex raid

The general consensus is yes...it counts.

But with Niantics intentionally misleading information that they like to call 'ambiguity', no one can be sure.

OK, cynicism aside - as far as we can tell, any raid will qualify you for the chance at an EX invite, and this includes Legendaries

I have received two EX invitations, for two different locations (one sponsored, one park) and the only previous raids I had done at those locations were legendary raids.

Yes. Even a previous EX raid at the same gym counts too.

There's a T3 and T5 egg at 2 gyms in a park near me, I'm probably gonna raid both. I'm very sure the turnout will be massive, as the gym where the T5 is on has already had 3 previous EX raid waves.

All of the people I knew from the raid boss group only raided 4 and 5 stars raids. And of course they received bunch of invitation from both 4 and 5 stars.