Need to invite priest although we don't know him well?

Yes - invite him because he's marrying you two. It's the polite thing to do.

Invite him. Chances are he will come to dinner and leave after. To me, you will know him well enough to have him marry you, he needs to be invited. I doubt he will say who, if you have met twice and he is performing your ceremony

Wow, I did not know this was an etiquette issue. We're inviting the priest marrying us, but that's because FH has a great relationship with him. If we were using a basic stranger, I don't think I would invite them etiquette or not especially when the ceremony and reception take place at separate locations.

Invite him to be polite. He may decline. If he does come, seat him with grandparents, aunts/uncles.

We are also getting married in a Catholic Church. We are not inviting the priest. Like you said, we don't know him very well and it would be awkward for all those involved. Who is going to want to sit at a table with a priest anyway? Haha. We are throwing in extra cash for the church fee so I think that is a nice enough gesture.

He will likely decline because most Catholic weddings happen a little bit before evening Mass and the priest will probably have to be there for that one, lol! It is nice to invite him though.

We are inviting our priest but we both know him and it turns out he is a friend of the FILs! If I didn't know him though I might not invite them, I'm sure he would understand!

I found this old wedding wire post:

https://m.weddingwire.com/forum-posts/757fba517fe49a08

It seems that these officiants don't expect to be invited and don't find it rude when they are not.

Usually you invite your clergy person.

If you've hired an independent officiant, we don't expect an invitation.

Thank you for posting this, I wouldn't even think to invite our officiant. Now I may think about it.