Thanks! Is it necessary that the brick also match the brick on the outside of my house?

Yes.

If they don't make a veneer for the brick on the outside of my house, is it okay to get close, or should I choose another material for my backsplash?

I would choose another material unless the brick matched perfectly.. I always have a heck of a time matching, maybe you should be seriously thinking of a material that you like, that will enhance but not duplicate the brick. What kind / color brick do you have? This walk looks better in a brick that enhances the stone, rather than trying to match a stone imperfectly. Brick looks better with slate or blue stone than a not-quite-right brick Brick and slate again Brick and slate Brick and slate again Brick and stone

My house exterior will be Gray Granbury and South Abbey brick. My granite is White Springs, cabinets a creamy white, walls a grey/blue/green. The bowl I attached is my color scheme. My theme is vintage/farm.

The brick didn't load. Another picture is the paint samples, granite, and on the side is a tumbled marble.

This is my inspiration house my floor plan and elevation is based on. Here is the brick and rock together.

This is my inspiration house my floor plan and elevation is based on. Here is the brick and rock together. The picture of the brick backsplash was my first love when planning the house.

Beautiful. So, the house has not been built yet? Can you use "real" brick, the same as outside? OR
Can you change the manufacturer of your brick? I found this site, they make brick veneer. I think, if you ordered the "real" brick from Old Virginia Brick or McAvoy birck or Watsontown Brick....this company apparently has the matching veneer. You'd have to call or email them. http://www.iabrick.com/index.html

The manufacturer does not have a matching veneer. I guess it's not feasible to use the whole brick on the backsplash.?.