A few suggestions are really rubbish, sorry. RPM 14m, had one, I was able to get going in 10 knots yes, but on a Nugget and I am 70 kg and consider my light wind technique advanced
RPMs (I had various years incl. 2015 and doubt the 2016 will be significantly different) are not really extremely grunty. They feel rather grunty but don't mix this up with high bar pressure "perceived" gruntness.
GTS3 has less low end than the RPM. So if you are after good low end forget about this one or buy 1-2 sizes larger.
If I read your post correctly you are after a hybrid/bridled C kite which will allow you to work on wakestyle/freestyle tricks but at the same time be more forgiving and have a higher wind range than a pure C kite?
In that case as kemp said look at the TS as well. And at the Enduro. Or even the 2015 Catalyst, which is pretty much the Enduro's predecessor. The Enduro also lets you tweak the kite using the wave/freeride/freestyle settings which do make a difference.
While I am not a big fan of the Cat pre 2015 I agree with others, it is not per se a weak kite in terms of low end.
Another kite I have flown which is similar to the ones you are targeting is the FX. Not a bad kite either.
When looking at 12m purely in terms of low end I would probably rank them Enduro/TS, FX/RPM/Dice, GTS. Did not like the Union for various reasons but low end from memory is not too bad.
Cauncy the man wants to do some wakestyle. How is the Boss, Rebel, Edge or even Switchblade gonna help him achieving this goal?