Starting to plan my DIY destination wedding

Hey everyone! I’m starting to plan my wedding, and since I’m Brazilian my fiancé and I decided we want it to be in Brazil (we live in Canada and his family is from the US, so it would be a destination wedding regardless of the choice of place). The thing is that I don’t have much money to spend; his family does and his mom is thrifting all sorts of things for us, but I would like to make it as DIY as possible for my part. I have a couple questions:

1) what (with the exception of services, like photography and music), in your opinion, CANNOT be DIY? 2) how many people can we invite and still manage to make most of it DIY? 3) and finally can anyone please help me with a timeline???

The wedding is next year, we’re thinking April or May, it’s going to be a beach wedding and all I have is the pallet and a Pinterest folder vahahah

Any help is appreciated ❤️❤️❤️❤️ thanks!