Pete, you need to read up on RFF especially that link I gave you...

Pete, you need to read up on RFF especially that link I gave you earlier.
I feel you do not have a grasp on their business model at all.
Just my thoughts from your postings mate. No offence.

In my opinion though I will attempt to answer your questions:

Which unusual farm is most likely? None.
Bees - No
Crocodile - No
Ostrich/Llamas - No
Ducks - No

What about diversify into grain? - Possible they may buy some grain producing land that has scope for value adding such as installing irrigation infrastructure etc.

Could rff do that? - Absolutely !

Buy a wheat or barley or corn field? - Yep but would be more like a whole farm, not a field.

And sell to their tenents? - No. they rent it to the tenant they don't sell it to them.

All in my opinion, DYOR

I also come from farming experience for 40 odd years.

Hope this helps Pete.