I have photocopied and scanned documents that have been encapsulated, without any problems. You can also photograph encapsulated documents, using a polarizing filter to eliminate the glare.
I use 3M double-sided tape #415 and have not had any problems with it releasing.
I have not actually written on polyester but if a Pigma pen doesn’t work, you could put a label in the margin of the encapsulated document (sealed in with another strip of 2x tape).
Hope this helps,