Yes it will make it look far to busy.

would go with either same color of tile for grout color.

or blend of counter color and tile.

but keep experimenting as you are doing,till you get something you are happy with.

The counter are busy enough without the arabesque pattern - accentuating it with light grout is making it worse. Go tone on tone - match the grout to the tile color.

I agree blend the grout with the background tile.

I love the combination GOOD JOB! Just use the same color as the tile It will look amazing

Don't try to match the tile and the grout exactly. Tiles look dark brown so go with a medium to dark gray grout and let the arabesque tile stand out but in a subtle way. You're smart to try a test area first with all grout colors.

It would all depend on whether you want the backsplash to be a focal point. If so you could go with a lighter colored grout. If you want to keep the backsplash more subtle I would pull the darker tone from the counter and use that for the grout color.

Now that's a real dilemma. You obviously chose the arabesque pattern because you like it, but if you use a light colored grout to accentuate the pattern, it will look very busy with your granite. A compromise might be a grout color that is just slightly lighter than the tile. Experimenting with several grout samples is your best option, as changing the color after the fact is not easy. Let us know what you decide.

What color is your grout?