But if I borrow from a specific source, my HELOC, only then I cannot deduct the interest?

Regarding your questions, in my opinion, you should look at your HELOC as one of many funding sources  & for every deal you should analyze which funding source (cash, your HELOC, refinancing one of your other multifamilies,....) is the most effective to use.

In sum, his main source of funding is to have the seller sign over their deed but maintain the financing in their name.

Doing your own sourcing rehab and renting is not the only way.

Additionally, if you are looking for some other good FB groups for military/veteran real estate investors, send me a message and I'll share the links(will get taken down if posted here), might get straight to the source of someone who's done this in Guam.

If I have a contract usually I'll try to target flippers in the area looking at various sources doing whatever I can to get in touch with them.

All great sources.

I would say its the vast minority of investors that only buy sherrif sales.. its a pretty tight group of folks that use sherrif sales as primary sources.. 

Has anyone used list source?

Looking to create relationship with a good source for funding.