Solid choices. I'm a firm advocate for a full Core helix. Esp when you have a pair of Hukka's throwing 18 dice before even moving. :-)
Gun Infantry are great for holding objectives (once they get on Overwatch that is) or clearing them - but Sweeper Inf are what you want for Storming.
3K is where you want your first handful of games, for sure. And the Adepticon event will likely stay small at that level. But comfy games are clocking in at 4K to 6K. Just cause everyone wants to field their Leviathans (as will you).
My limited experience says that we're all going to start working out strategic and tactical preferences, and discarding and including units to suit.
Neat observation on the Hukvokka Heavy - Two Designators means you can zero-in an Artillery Marker with one, and use the other to call in the Arty all in the same activation - a single Designator can only do one or the other. Just save his activation til the oppponent thinks his Nyx are safe in the building, and BAM. :-)
I think you'll really enjoy the Veydreth helix when you get around to them. And your recon helix includes Jagor Walkers, the only guns in the game with both Ack Ack and Pinpoint - best heavy flyer killers period. Directorate Wraith Leviathans should run from those in terror.