How about plants? Gravel? Place some chunks of the grey stuff (concrete" that cover the gap and a bit of the edging too? I don't think your border is going to move much, except for the inevitable frost heaving. If you re-set anything that has shifted in the spring, you won't have the big rebuild effort.

Grade away from a building for a paver patio will be somewhat less of an issue because of drainage afforded by the space between pavers and the base upon which they rest. Your 1/10" per foot grade is probably safe though I used 1/8" per foot because my level gave that indication. Remove all of the top soil and sufficient sub soil to allow for the base. Base requirement is dependent upon your frost zone and the weight to be set atop. I have a minimum of 5" base plus an inch of sand but below a hot tub I have 10" of base. Paver base need not be different only because it's further from your house. Now, here is my advise for new construction - WAIT, maybe 3 years. Why, because the foundation backfill needs time to settle completely. Most likely your existing slab is going to shift (unless footings were poured below) during this time so whatever pavers placed alongside will misalign in a season. Yes, a photo would be helpful, many are posted. And, do you mean 2,000 sq. ft of pavers, not 200? Personally if you're going that large, why save the existing 100 ft of concrete? I'm linking our patio. When I built it in 1998 (1995 home construction) I set stakes and provided a crowned grade from the house and to both edges. Because I needed a retaining wall, I installed French drains below the gravel,to carry away any water and they have worked great. Hope this helps. Good luck. Here is a link that might be useful: Patio

I don't think it will wash away with rain. Take pictures of it and bring it to a mason supply store. They might have a product that will dissolve it. Muriatic acid might be a solution. It all depends on what the chemical composition of the white substance. You need to be very careful with this product and wear protective gloves, goggles, long sleeves, long pants, etc... An internet search should give you the correct safe method of diluting and testing it on the bricks. Ron

"... nothing more maddening than pavers with bad tolerances..." Though frustrating, as it was my first DIY experience with pavers, it ended up being OK once I was able to get beyond the mixed colors, which all came at the beginning of the install. The drive was probably 80% one color and 20% mixed. If by "... ripped all the pavers down..." you mean CUT ... on the saw ...?? As it was, I had two solid days of non-stop cutting. It was winter. My hands were numb from wet and cold. I either got tired of changing gloves or ran out of them, don't remember, but had on crappy, sopping wet cotton gloves with all the fingers worn through. I didn't discover until the end of the second day that I had flat worn off the pad of every finger down to the meat! OMG, it hurt soooo bad when they all dried out! I couldn't touch anything for a few days. That was enough cutting for my first paver project!