1) Rental home -- mortgage is tax deductible, and you are likely already claiming it
2) Do you itemize and get the mortgage tax deduction (I assume SFO = yes)
3) HELOC -- If you have money sitting around, I would pay off the HELOC, then borrow a similar amount to invest in non-registered income producing funds.
Assuming you get a 30% tax deduction for these, that makes those interest rates net out to
1) Rental 4.25 x 70% = 2.95%
2) Principal home 3.625 x 70% = 2.55%
3) Heloc 4.25 x 75% = 2.95%
4) Car loan 1.99%
If you have a 50% top marginal rate, and the tax deduction is at the marginal rate, that nets out to:
1) Rental 4.25 x 50% = 2.13%
2) Principal home 3.625 x 50% = 1.82%
3) Heloc 4.25 x 50% = 2.13%
4) Car loan 1.99%
By these calculations, the HELOC is the winner, by a very slim margin.
Meanwhile, investments --> could you beat 2% with money in non-registered investments instead of paying down debts as quickly?
Emotions-- do you want to kill the cash flow drain of $400 going to car loan?
Other?
You have no bad choice here, crazy30!