I see
ElenaRu has already answered most of your questions. I will still answer them since it was mainly directed to me (I feel obliged :
)
Just one copy, filled out by sponsor but signed by both sponsor and parent. I chose "parent" (but it's confusing).
Read my previous post: http://www.canadavisa.com/canada-immigration-discussion-board/tips-for-2016-future-pgp-applicants-t333951.0.html;msg4832567#msg4832567
You can leave it blank.
IMM5669 doesn't have those fields. If you're talking about IMM5406, I wrote "Not applicable" in
Marital Status column and "Diseased on DATE in CITY, COUNTRY" in
Present Address column.