First list.
I don't think it's a good idea to leave your
VP warlord out in the open with 3 wracks, they're T4 with a 5+ save essentially, with any S8 shots denying that crucial
FNP save. 5 Wyches without a haemy to give them
FNP, no
PGL to get that stealth(6+ is better than none), you're probably gonna see very limited use out of that unit. I'd consider making them HWG unit instead, as your list is gonna suffer if your opponents bring some heavy
AV unit(I've seen 500pt necron list that can fit 2x Anni barges in, for example).
Using the 1st list as base, I might do something like: Haemy + 3 wracks on a venom, 5 HWG wyches on a venom, ravager, and a razorwing jetfighter. The ground troops may have to do hide and seek on the 1st turn or 2(depending on your dice roll), which, with the help of the new nightfighting rules, might make it possible.
Second list.
Certainly an interesting idea, but my question is again, what do you do if you run into a mech list? Or even, try fielding your 1st list against the 2nd, what will be your plan? Your wracks won't even be able to harm our own AV10 vehicles, let alone the tanks
IG and others can bring. And as you've noticed, covers will be really important for the 2nd list, which, your
FLGS doesn't have a lot of... I think it could work if you have enough cover, those
MCs are big fire magnets, you want to give them covers in case any low
AP weapons go through.
If there is enough cover, I'd definitely give the 2nd list a go though...