Yup you could start the harlies in there , though it would be 1 Gajillion points of fail in one place that can have your day ruined with a single lucky shot ...
Vects car is a crapfest, vect is pretty good but mega expensive and does little for the rest of the army like other similar 5th ed characters do , then we talk about quins, they were not particularly brillinat in the CWE book without psychic support , with it they are pretty good and probably worht the outlay.
They have no place in a DE army to be honest , Incubi and wyches do it better for less.
Sadly no, the veil of tears does nothing for a vehicle, it should , but then again hammerhand should not stack .....
Sure run it out for fun , it might work in a casual game , its asking for miserable punishment in a vaguely competitive setting.
Rant in E Minor