...is it worth it for the convenience of having someone coordinate and handle the whole project for you? Although we DIY the majority of projects around the house, cabinets and counters were something we felt best left to 'the experts'. We didn't want to risk making any costly mistakes on our own. ...are you limited in materials selections? I don't know how unique this is, but we were told we would not be allowed to visit the stone yard and pick our slabs (among the granite 'swatches' available to us). The owner told us if we insisted on viewing and selecting the slabs (who wouldn't?!), he would have to "put a KD" on our project. Really strange, and in hindsight, this should have been a red flag to us. While they had an array of drawer hardware and appliances displayed, we weren't required to purchase through the shop. Just from the few replies you've received, it's clear every firm operates a little differently. Ask lots of questions and take notes. Above all, be sure to get references, and don't think a firm's competent based only on Houzz awards and 5-star online ratings. Good luck!

The design build firms are going to be more cost focused. Not your needs focus. They may have a designer but this person is not really focused on what you want and need. Most likely the designer from the deign build firm is there to ensure you make choices so the build can start and the company can move on to the next project. I would go with someone who is there just for you.

Epoxy is overkill outside a commercial environment. It doesn’t provide the benefits that you think it will for it’s difficulty of application. An acrylic or urethane based grout is more than fine, unless it’s natural stone. Use natural stone with with caution. You want a high quality cementitious based grout with it that lets it breathe and dry out. What is more important is the waterproofing system behind the toppings, and the person installing the system.

Do you have a Habitat for Humanity store or something similar in your area? You might consider trying a place like that and keep an eye out for nice cabinets that have been removed from another house that you could use in your remodel. Sometimes they have the counters too if they come out without breaking. Often these are removed from really large homes and there are enough cabinets for a smaller home and the extras can be used to make filler strips etc to make it look custom to your home. This is rarely an overnight exercise -- it could take quite a while and lots of searching to find something that could work, but it would be more budget friendly than all new. With your current budget you'll be choosing from the bottom end of the cabinet market. Also with your budget you should be considering that you might need to do some of the work yourself which is going to be tough with small children. You mentioned you can save $1000/month. Even if you waited a year to add to your savings that would make a significant difference to what you can afford as well as a contingency for other things that will definitely come up, its not an "if" but "when" when you start renovating and taking out walls. Plumbing or electrical or both could give you issues or pipes might need moving, venting moved etc. Plan carefully and come up with a "must have" list, then a "nice to have" list. Work with someone you can trust and work through what you can get from your must have list with your current budget. Good luck and congratulations on the new home.