Here is my reply to a similar question a while back: For $6k, the type of "show" you will be going to will not be the type of "show" you expect.
One question that I have is the "5-6 coats of clear"... What made you decide upon that number? Unless you are talking about having it "flow-coated" (where the painter lays down 3 coats of clear; then wet sands to a perfectly flat surface, which takes most of two coats away; then lays down 1-2 more coats of clear), that would likely be too much film thickness. It would likely end up with a milky finish that would be apparent on that color of base. If it is not being flow-coated, I don't know many painters who will want to lay down that many coats of clear. PPG recommends a maximum film thickness of 3.5mil, and 6 coats would effectively "void" their "warranty" (which is not worth much anyway...just sayin').
Also, I would not consider Lizard Skin on the frame. The two versions of Lizard Skin are for: sound control and heat control. That is the only purpose, neither of which are needed for a frame. Now, as an interior use...absolutely! I have used it with great success for both uses. I have found the the heat control does a decent job for sound control, too. But, the sound control does not do that great for heat control.
For the frame, sticking with paint, powder coat, or even "bed liner" (from a reputable shop who understands how to plug holes, tape off, etc) will be your best bet.
As for the estimate for a "show quality" finish, if the bids are under $20k, I would be suspicious... Many shops (myself included) now work off of a "base rate" with money held in an escrow account on jobs this big. Basically, you put down an agreed amount, let's say 10k, in an escrow account that both you and the shop are named on. An agreed amount is immediately available to the shop to cover overhead and starting supplies (let's say $3500 of that $10000). Then, the shop "bills" the escrow account as work progresses. I bill every two weeks. This way, your money is only used when they are working on your vehicle. This is because there will be many other vehicles worked on at the same time that your vehicle is in their shop. There will likely be a "mechanic's lien" on your vehicle for the duration of the stay at the shop. It just says that you cannot have your vehicle back if you owe them money (usually it says "any amount owed over $0.01USD) until you settle the bill. If you should "pull" the build at any time, the shop will retain a set amount or the owed amount (whichever is higher), release the "lien", and you will receive the remainder of the money in the escrow account and get your vehicle back. This protects both the shop, and you.
If I were going to do that in-depth of a build with someone else doing the work, that is the way that I would want to do it. I have been doing it this way for quite a few years. I have only had one upset customer, and even we have since came to an understanding of why I could not "bump him up on my schedule" and he even had me do more work to his car later after taking it from my shop.
I have never been left "holding the bag" by a customer...and a customer has never needed to feel like their vehicle was in "shop jail".
Sorry for so many words, but it seems like you were looking for details.
BTW...I am in East TN. I do not know the legal side of things for your specific location.
Best of luck! Looks like a real good start.