Tax questions

I originally purchased a property under ABC LLC (owner 1 and 2). Then created EFG General partnership between a DEF trust and ABC LLC. The trust has two trustees, one of the trustees is owner 2 and the other is an unrelated investor. ABC LLC deeded the property to EFG partnership.

1. For tax purposes, does EFG partnership file a schedule K for the trust and for ABC LLC?
2. Does the partners in EFG partnership have any basis in the property or is it that ABC LLC will hold the basis because it originally purchased the property?
2a. If so, is the basis the same as ABC LLC's basis at the time of transfer?
2b. If not, does that mean that all proceeds of the sale of the property considered income if sold under EFG partnership.
3. If the property was deeded back to ABC LLC, would the EFG partnership still need to file a return and would the DEF Trust still need to file a return since no income or expenses took place in either entity?

Thank you.