I'm tinkering around right now with BIML via BIML Express, in VS 2015 Community Edition & SQL Server 2016 Express installed locally (named instance). Works fine enough for me!
From what I understand, BIDS Helper 1.7's BIML gets disabled for VS2015. That's OK, the other bits besides BIML still work. So, jump thru Variegence's hoops, get key, and download and install BIML Express. Despite find-and-replace (only find works) not working currently in BIML Express, not fighting with the normal XML editor's Intellisense quirks w.r.t. BIML is quite nice.