Is Leasing a good option if I need 15K miles per year

If the captive doesn’t allow transfer they aren’t listed on Swapalease typically (Chase/Subaru). Nissan/Infiniti & VW/Audi are the two I know of where you are still liable.

I wrote a long post about my experience with Swapalease which may help:

Success/HorrorStories with Swapalease?