Welcome to the thread, you have excellent ideas.
It is fantastic that you found extra land to farm, that is a miracle in this day and age.
Will the crop be safe? Does the owner live there? Did you put a contract in writing?
Without a contract, you could find someone else owned your crop, at harvest time.
A seed swap, would need to be cleared with Mr. Robinson first, I would think, as he would be involved as the owner of the site.
I see nothing wrong with it, gardners have always shared what they had, plants and seeds multiply, that is God’s intent.
You might find you want to take full control of the project and it could be done as a Freeper project, but using a Yahoo group as the base for it.
Here in the Kingman area, we found the old varieties and some of the oriental greens would grow, but the new hybrids do not produce at all, we are dry, hot in the day and cool at night.
Good luck with your garden, you will find out what real work is and also the joy of seeing all that food growing.