1. Do I have to fill out Form 8865? what filer category?
Form 8865 is required to report information with respect to controlled foreign partnerships, transfers to foreign partnerships, or acquisitions, dispositions, and changes in foreign partnership ownership. You would each be Cat 2 as you each own more than 10%.
2. In addition to this Form 8865, do I have to fill out a Form 8858 "Foreign Disregard Entity"?
Complete only the identifying information on page 1 of Form 8858 (for example, everything above Schedule C) and Schedules G and H on page 2 of Form 8858. Do not complete the separate Schedule M (Form 8858). You are not required to complete Form 8858 if there is a Category 1 filer of Form 8865 that completes the entire Form 8858 and separate Schedule M (Form 8858) with respect to the FDE.
3. What Part of Form 8938 should I complete?
Your Foreign Partnership interests are reported on Form 8938. The property is not reported but the foreign entity itself is a specified foreign financial asset and its maximum value includes the value of the real estate.
Part II would be a summary of the partnership assets.
I would strongly suggest you have a tax professional complete these forms for you at leats if this is your first year.