This does not sound good to me. First of all, you only mix stain with polyurethane to 'correct' problems with a final result. Stain, dry time and then coats of finish is the way it is done. But, perhaps, this method is something new, although I have never heard of it. Second, your premixing the stain is a cop out for the sub and the contractor. If you aren't happy with the result, it won't be their fault...it will be yours. Third, this sounds very unprofessional to me. You are wise to be concerned. Fourth, definitely have the floor person do samples and then only proceed with the work after you are happy with the sample color. Fifth, It appears to me that you are working through a general contractor, and that puts you at a slight disadvantage when trying to work with a sub. However, you have a right to inquire about a subs qualifications and skill to give you what you are paying for. You even have the right to know the brand name of the stain and the type and brand name of the polyurethane. Good luck!

What are you trying to accomplish? Minwax has a broad variety of high quality products. I've used them for decades on many kinds of projects, and I find it hard to believe that they don't have something suitable for whatever home application you have in mind. If you can't find what you want on their web site, give them a call: 800-523-9299.

"Any idea what this white haze is and how to fix it?" I have an idea the white haze is "blush". I wouldn't commence to tell you how to fix it because I don't know for certain what was used from start to completion. If there were a prize being awarded to the party who correctly guessed,I have a couple of guesses. Guess #1. The finish isn't oil base polyurethane we are most familiar with. I had this exact problem with waterborne urethane when it came on the market several years ago. I have since contacted more than one manufacture asking for dew point chart but has no success. The temperature and humidity (aka dew point) were wrong when the scratch repair was attempted. We have known about shellac blush and how to repair it for a long time. Up until now,I haven't found an equally effective method of fixing modern waterborne products. I fear you will have to go back to square #1 and start over. Guess#2. Shellac was applied between original coat and repair coat of finish (very coomon practice). The shellac blushed. Carful hand sanding to remove repair coat and shellac coat "MIGHT BE POSSIBLE"but I'm not optimistic. Those are my GUESSES,better known as wags.

The "recoat" time will have taken into consideration the time that you can step on the floor (with clean shoes and PAINTER'S booties). Again, DuraSeal is a low grade product. I'm not entirely convinced the "1-2 coats" of finish is going to give you 7 years, let alone 15+ years. Remember: low grade water based = short wear life. And DuraSeal is ranked as one of the lowest grade "professional" products out there. They are only slightly better than Minwax (owned by the same company). You appear to be concerned about wear life....1 coat of DuraSeal (or even 2 coats) will not offer you the wear you are looking for. This is almost guarantee that you will achieve a floor that wears out too quickly (which is the same as the complaints you listed above). You need to move the DuraSeal's High build formula. Please be aware of what you are "buying into".