Your contract should include "ARC approvals will be obtained by you or the contractor before commencement of work"
IMO you should be getting quotes with your own sketch of the landscape design indicating the trees bushes etc and size range of each, bedding etc.
That way your shopping and comparing the same work.
Also include a "drop dead date of completion"
Too many folks get quotes with different contractors using different plants or designs.
someone will be on the losing end that way
Lastly NO MONEY upfront, if they don't have the $$ to buy the supplies on their own and need you to finance their their biz find someone else.
The approval process is very simple not a big deal, basically setbacks and % of grass removal for the most part.
But if you're doing something way different like I did it can be a PIA, like 4 meetings and compromises (mostly on my part)
. But finally came to an agreement on using Fl natural's with high % of grass removal.