I think you should hire a reputable escrow that would hold the 100 BTC because that is a large amount of money. And honestly speaking, I will not entrust this to a single person like you. And the plans were not that clear though. I think you should put real photos for the site and not by wiki map. Then crowdfund is safer if you create a site with your plans of course (stated creating a site, that should be included). Well, Good luck with your project. I don't see it being a successful one. But, building some trust and clarifying your plans will help you succeed with your project.
Yes, good points. OP doesn't have anything concrete yet, just plans... Looks he is starting to search for the "land" to buy. When he does it, please, post here the pictures, so we can see the place.
OP, keep doing your project step by step, check everything first (the prices, the place, if it will work or not) before asking for money.
And one question: People from other countries not in Europe will be able to enter there in this community? And how would be the laws there, same laws of Estonia?