If you really want to bubble wrap your tanks, blobs are much better option for that, than veterans. They cover large area making a deepstrike at half range of a melta gun impossible.
That is a good idea. Because I know there would be some DS Brutes with MM that could cause some problems. However, I feel I wouldn't get the most out of them with no one to give them orders.
I would also personally put Pask in the punisher, because having rending on it is really great, much better then firing large plasma shot, because if you wanted that kind of shot, you could take a demolisher in the first place, which is S10 and does not get hot.
Does the punisher have rending? Is that in a FAQ because the codex doesn't say rending. I went with the plasma's, because, maybe this isn't correct, but with preferred enemy, I can re-roll the 1's for get's hot? (Plus the plasma have increased range)
I am not a big fan of leman russes armed with battle canon, because a basilisk is cheaper and it can do a similar kind of work with its barrage earthshaker cannon.
I would love to take basilisk(s), however, the minimum range on the earthshaker concerns me, as after turn 2-3, every enemy unit will likely be withing 36".
Against Chaos, you really need more AA guns. If your vendetta gets shot, you'll be powerless against heldrakes. You could perhaps give some AA missile launchers to your veteran squads. Not exactly the best option available, but it's a possibility.
Yes, I agree with that. Maybe add the aegis defense line with AA gun, to be manned by vets (remove the chimeria, or replace the group with a blob).