Hi Marta,
Welcome to Permies! Congratulations on your new farm. So exciting.
I honestly don't have a specific
answer for you, but I would suggest that since these folks are your neighbors, that you reach out to them as a neighbor. Keeping on good terms with neighbors is vitally important, in my opinion, especially since one never knows what's coming down the road.
It sounds like you might be using the acreage yourself next year or soon after. Is that correct? If so, they need to know that, so they have time to make other arrangements for their needs. In that case, maybe as a gesture of good will, keep the current lease similar to what they're used to, or at least something simple.
If you think you might lease it for longer, perhaps there is someone else in the area who leases to Amish folk? They might be a good resource to ask. You're ultimately dealing with a community, not just individuals, so consider everything you do as an investment in establishing lifelong relationships there.