Taking control of property after puchasing junior note at a discount.

Anyone out there with experience of taking a property subject to after purchasing a junior note at a discount?

For example:
ARV : $400k
1st TD: $250k*
2nd TD: $150k

1st TD is in foreclosure.
Contact the bank of the 2nd Td and purchase for significant discount ($10k-$15k) since that note gets wiped clean at trustee sale. My understanding is that since you are simply purchasing the note at a discount and it is not in 1st position, you don't need permission from the homeowner.

Get property Subject to the first loan and cure the 1st TD. Homeowner is motivated to do this because they still owe $400k

I suppose technically this isn't a short sale but didn't really know where else to post this.

My questions are:
1. Is it still the loss mitigation department that you contact to purchase the note?
2. What kind of homework or paperwork do you do to make yourself more credible to the bank?
3. How do you approach the homeonwer?
4. what other things should I be aware of?