My mother was probably my biggest helper. I also planned a wedding from 5 hours away (near my family’s cabin), so my mom did a lot of the scouting for me.
For instance, she did a lot of scouting of churches with/for me. Once I chose a church (the one nearest our venue and cabin) my mom helped with some of the details since she was there almost every weekend. That way when I came, I could just talk with the priest about the ceremony.
She also helped me put together the invites (addressing them, stuffing them, mailing them). But all of the design and order I did myself (other than my Fiance picking them up).
She also helped us by finding a baker with good prices and picking up our taster cupcakes from the bakery so that we could just try them when we got to the cabin instead of having to make a special trip.
Who of your friends/family are in the city where you’re getting married? Can they help you by scouting- meaning maybe they can visit bakers, florists, etc. with your inspiration photos and get estimates, get a feel for the vendors, etc. and narrow down the choices for you so that you don’t need to arrange all those visits yourself? Or, if you are trying to find officiants and videographers remotely- your Maid/Matron of Honor or BMs could do it too!
For the invites- can you just hand that off to a member of your FIs family? Do you care that strongly about them? Perhaps just give them the English language invite and ask them to make one just like it in the other language?
I think the best way to delegate is to decide which things are least important to you and then hand them off. But you have to decide that some things aren’t important- otherwise you’re just micromanaging. For me I didn’t really care about the cake- I tasted the flavors, e-mailed some inspiration pictures and just let it go.
Also- ask your Fiance to help. Put him in charge of something and then trust he will do it. I put my Fiance in charge of our afterparty. I was worried because he’s a procrastinator, but it turned out great. Maybe your Fiance can handle the invites. (Now I know you said he was working on his thesis- I have a PhD and have been through that myself. He can’t work 24 hours a day. He can take a break from writing/editing/etc and see to an invite!)
And remember that your local board might be a good place to get recommendations on officiants and videographers!