I pitched the same blend into a batch of belgian apricot wheat back in January 2009. It did continue to sour over the years. The last time I checked, the ph was right around 2.8

. Yes it will continue to get sour if you leave it at room temperature. With the gravity at 1.010 after 14 months, the amount of sugar is so low that I doubt bottle bombs will be much of a problem.
I took a bottle of this to a beer fest a couple months ago, mostly for entertainment purposes. It was a blast watching other brewers taste it. (I do have a bit of sadistic streak

)
The Brewcasters did try a bottle of this stuff a couple years ago at the end of one of the shows, but Beevo was the only one who liked it. It had developed a bit too much acetic acid and pedio. I have since learned that the best way to keep those under control is to start with the OG high enough that the alcohol level will rise quickly enough to inhibit the growth of those organisms before the taste gets out of hand.
Like you, I plan to use some of this "Ultimate Sour" beer to blend in small quantities of other beers.