I agree with changing Valliance for an elemental gun (my current favorite is Argent Peacemaker because of the mobility, 6 bullets per clip and not detrimental to the team in any way).
For Electron Vortex vs Shiver, it's not really about FSC, since EV is better for undeads, it's about Vanaduke. You want Shiver for Vanaduke, EV for everything else (unless you play with beginners, if you do so, Shiver may be more useful).
The rest is ok, but your first Shadow Lair with full Vog is going to hurt. You may want to consider a Skolver part somewhere, and a Crest of Almire to have a shadow shield.
Consider exchanging the Valiance with the Polaris, but only do so if you have difficulty against turrets.
As for the bombs, both are useful as support, and really it boils down to whether or not you will be doing a lot of FSC. If yes, the pick Shiver, if not, then the Vortex.