The capability of having real-time stems on standalone devices has been discussed in a variety of threads here (there is a search function link at top right).
Check this
Maybe InMusic will surprise us, be there are a lot of doubters that standalone devices will have real-time capabilities anytime soon. Certainly, the quality won’t be as good as that done on more capable attached computers.
For now, you can use the current SC Live 4 (and, of course many other controllers) with Serato, Virtual DJ and, somewhat with Algoriddim djay Pro. The latter two have the best-rated stems.