With the free points you get from removing the chaplain you should have more than enough to purchase a razorback for the tactical squad. You'll have enough points to give it a wicked cool gun too
A tactical squad the way you have it laid out is a good tactic (pun intended) and may work great for you over a normal assault squad (sorry I refuse to shorten words like assault to ass

). You'll have a back field unit providing fire support with the
PC and holding an objective at the same time. I see no problem with that.
Edit: Your new list seems pretty solid. I'd personally like to see the
LC dropped from the one razorback to help field a second razorback for your tactical squad. But, doing so will be limiting your anti-tank which is hurting a bit in this list. Just a thought.... Good luck!