Hello,
In my view there is no restrictions regarding where you get the loans from.
You must register with the PTRB in order to avail of the interest deduction.. I think currently 85% or 100% if to HAPs .. but the interest deduction is only available on letting the property .. so that will only be available once the property is renovated.
I would point out that you should have loan documentation in place with family, agreeing term of loan, the principal and the interest rate and how the interest is calculated and when payable and what recourse the lender has if you miss payment.. otherwise revenue could view the entire loan as gift or just the free use of money as a gift ..
I’m not sure on the following- someone else might be able to provide clarity .. the lender will be subject to income tax on loan but is there a withholding tax obligation???? Really not sure about this aspect ...