Too Much Cherry Concentrate?

I have a question regarding the use of cherry concentrate I acquired through a local club group buy a few months ago. Here is the link to what we got...

Cherry Juice Concentrate: A natural alternative to fight arthritis and gout

I brewed Jamil's Black Forrest stout, let if ferment for 13 days, then racked into a secondary and added a 1/2 qt of the concentrate. I let it condition for about 3 weeks before I racked again and tasted. Wow, All I could taste was the cherry. My gravity when racking was around 1.018. I didn't measure the gravity after adding the cherry concentrate, but when I tasted, the gravity was around 1.021. There wasn't as much fermentation activity going on as I expected when I added the concentrate.

So I guess my question is this...Options:

1) Should I pitch more yeast (I have Montrachet and Lavlin D-47 on hand, originally used Wyeast London Ale) to try and eat the rest of the cherry sugar? I don't want to dry the beer out too much. Can I add a smaller portion of the dry yeast packet?
2) Should I start adding lactose to try and balance out the tart flavor?
3) Should I RDWHAHB and let it age for a few months?
4) Have I caused death by cherries...Feed to the sewers?

1) Should I pitch more yeast (I have Montrachet and Lavlin D-47 on hand, originally used Wyeast London Ale) to try and eat the rest of the cherry sugar? I don't want to dry the beer out too much. Can I add a smaller portion of the dry yeast packet?
No
2) Should I start adding lactose to try and balance out the tart flavor?
No
3) Should I RDWHAHB and let it age for a few months?
Yes
4) Have I caused death by cherries...Feed to the sewers?
Maybe and no

Although you violated the "add to taste" before bottling guideline.