If that $760k was all used to buy, build or improve the home, that portion of the interest goes on Schedule A.

For the $50k that was borrowed in 2015, it depends on what it was used for.  But be aware that a portion of that may have been paid, so that $50k may very well be less than that now, in which case your numbers don't quite add up.

For the $200k that was used for purchase a rental, that portion of the interest goes with that rental.

For the $50k that was used to purchase another rental, that portion of the interest goes with that additional rental.