Would you consider using another material for this addition, such as board and batten or some other kind of siding? (Or glass block?) Even if the bricks are similar the mortar won't match and your addition will be obvious. I have run into this with trying to match brick for a fireplace refurbishment. We did the best we could, because the homeowner didn't want all the brick removed and reinstalled, but even with the meticulous attention of my brick-layer, you could see the difference.

There may be other solutions, but it would help if we could see the exterior elevation of that side of the house (and the front of the house, as well).

I'm not really clear on the issue with the roof. Maybe someone else will "get" that and have a comment or recommendation.

your best bet is to talk with a local brick distributor, they should also be able to help you match the mortar close enough - these guys do this kind of thing all the time.

Any local brick distributor should be able to come out and tell you what the brick is and whether it is still available. I would think your contractor has already had them out?? If it is not available, then I agree with Cynthia that another material would be better. Is there a way to use rock and hardie board or something similar? Don't understand the issue with the roof. Do you have plans you can post?

I'm adding photos of one of the sides with the add-on (behind the hot tub). We're considering taking the brick off that entire wall, putting rock there, and using the brick on the other side and around the back. RE: Cutting the addition in 6" on each side would mean the roof and inset sides would be similar to an eyebrow. Note: while taking additional pics I noticed the fireplace (on the left) is an add-on...different brick and different mortar.

Matched brick is never the same. Use concrete board or such for your addition if you are worried about it matching.

What about doing an espalier on that wall? Rather than taking off the brick? Didn't realize that the addition was already completed. This would give you something interesting to look at when you're in the hot tub! Here's a few pictures to show what I mean:

The house hasn't been added on to yet. We'll be adding 12' to the right side of the photo.