I think your quilting looks beautiful and you're going to have so much fun using individual quilting designs for each block.
Your Chaco liner tool is one of my favorites - and yes, blue, yellow and pink would be good additions.
I like my Frixion pens, markers and highlighters. I've never had a trace of them show up after laundering - not even the "ghosting" that shows up after ironing the lines away.
Years ago, I tested the Crayola washable markers and wasn't happy with how poorly they washed out. A few weeks ago, I noticed that everyone seemed to really like them, so I did another test of the Ultra Clean version (or whatever they're called.) I colored heavily on a piece of washed muslin, marked the colors with a Sharpie and ironed the lower half of the test area, really getting it hot and waited a day or two.
It went into the laundry without any pre-treating or bleach and it came out sparkling clean - only the Sharpie labels remained. So I would not hesitate to use those now, either - except for quilts which aren't going to be washed right away - wall-hangings, table runners, etc.
Best of luck!
I am really enjoying all the pictures posted to this thread!