Hello Jacki, The toilet width is 15-5/16 inches and the depth is 28-7/16 inches. You can view the spec sheet here: https://images.homedepot-static.com/catalog/pdfImages/61/6153f23e-6078-4197-a1f5-228bd2c450f4.pdf I hope this is helpful and thank you for you interest in TOTO!
WASHLET+ means theres a hole for the T40 bidet. So the Legato WASHLET+ and Aimes WASHLET+ both require the T40 bidets. Looks like your Aimes MS626214CEG is not a WASHLET+ so there is no value to puchasing a T40 bidet (in my opinion). C200 should work fine I think but get a second opinion or call Toto customer service.
Yes its compatible and an easy install (providing you have the GFCI protected outlet) and your water service is appropriate. You won't see cords coming out the right side (as you sit on the toilet). If you're hoping to hide the tubing and electrical coming out behind the toilet (after exiting the hole) the water service and outlet need to be positioned appropriately. You have to pay attention to the tube routing and tuck the outlet in tight to hide the cords assuming its a new outlet install (but not so tight you can't insert the pIug). The outlet was a new install and hiding water service and outlet behind the skirt was important to me. I had to reposition the water service to clear the skirting and have access to route everything. I installed the 500eT40 washlet in a 1st floor guest accessible powder room. I did not want the lid rising each time someone went in to wash their hands so did not want the 550e lid opening. There is still the pre-spray noise from the motion-sensed approach.
It's NEVER a good idea to stand on a toilet cover(sit ok) as the cover can wiggle. The intent of the cover is a safety feature. Use a step stood, ladder for bathroom maintenance please.
The T40 washlets, only
It is manufacture applied so yes. I think its some sort of coating to smooth out the porcelain. Like a polyurethane coating (but not polyurethane.)
Yes. In the future I will purchase a bidet.