I wish the OP luck, he has a task and a half to make it work even without the issues of wet land and it never having been used for plant crops. I do think we are better sticking to positive advice and leaving any negativity behind. It is hard to do this when you feel you are getting criticised from all sides. However to the OP I would look seriously at the advice given as we have experienced people on here. Real time served experience that is worth a lot. Of course you need to pick and choose what you want to take on board for yourself and accept the consequences, but it is still worth listening.
I once met a guy who was in the process of turning land into a commercial and self sufficiency project. IIRC it was up Kentmere valley and it was land that had never been used for growing plant based food. IIRC he was about 2 years into the project and still had not reached full, year round, self sufficiency, let alone producing in quantity for commercial veg box business. He was starting to feel the pressure as he was running low on funds I think. I met him in a walking group and I think he needed that activity to destress from his venture.
I finish this post with another wish of good luck in the OPs endeavours. I do wish him success in it, even if it is hard thing to do.