I decided to file just to be on the safe side. If possible, do you know what kind of sheet/form i must attach regarding part V in form 5472?Yes, but it doesn't mentioned 5472. Some accountants says it's not extended. But I'm not sure as 5472 doesn't seem to have its own deadline.
If there are no transactions then you shohldnt file. But I think it's not clear that those are not transactions on behalf of the business. If you created the llc in 2019 then I believe you should file anyway as that would be a reportable event.