Schedule K-1 Form 1065

Hello,

I'm using Turbotax  Premier 2025 to enter Schedule K-1 for Partnership Form 1065.

- Line 16 is checked off and schedule K-3 is provided.  If all the income is from US and there are no foreign taxes, can I just leave it blank? TT says I can but I want another opinion.  

- Box  20

  code U - I have a statement with "Goodwill" description and original basis, accumulated depreciation and remaining basis.  What exactly do I enter here?

  code AJ - I have a statement with aggregate business activity gross income amount and aggregate business activity deduction.  What do I do here?  TT doesn't support the form 461.   Can I skip it if ?

Thank You for all your help.