I agree with not being a perfectionist.
I am working on a signature quilt too - and was surprised by some of the blocks I got back - I think my favorite has to be the class that signed on the freezer paper on back instead of the fabric front... I did figure out a way to trace their names onto the fabric so that they didn't miss out, as I got the blocks back on the last day of school.
With the brick layout, I don't think you need to fret about perfect seams as it looks like a very forgiving layout. At least you don't have signatures that lap over or are completely in the (marked) seam allowance... Been there too.
Have fun, and I know they'll appreciate the quilt.
Cheers, K