There's no such thing as a renewal;, you need to male a new application.
Parents should provide proof of their personal funds, not yours.
Invitation letter is not a requirement for TRV.
You are in a tough and understandable situation but the one who has full custody has all the cards unfortunately and decides what's best for the children. You need to start with a custody issue.
1. Send a Use of a Representative Form (IMM 5476) via webform.
2. The lawyer's access will be revoked.
3. You can link it in the express entry account.
It might be okay. But do attach your explanation, show your efforts to get a corrected birth certificate and provide some estimate when you can get it.
Agreed AOR arrives next day tops.
You can apply for BOWP after AOR, but IRCC will start processing BOWP only after your PR application completeness check is done (that;'s about when you get biometrics request, 1-3 months).
Your PR status cannot be revoked due to your diagnosis if you were diagnosed after you became a PR and you didn't misrepresent it during your PR processing.
It's much safer to seek H&C from within Canada.
You are good if you have solid proof of your treatment/diagnosis and also you are not able to move until August 2026 specifically due to your treatment/diagnosis. You will be allowed to enter anyway with a possibility for H&C.
There's no way you can upload it in the wrong place. The upload button specifically appears for the PFL purpose and you cannot miss it really. It pops up only if they request something.
Depending on the profile of your parents: ties to return, travel history, medical issues, personal funds (not yours). And of course you need to be eligible to be a host for super visa applicants.
If the profile is strong, you can try for a tourist visa. If not. you would better opt for super visa
If you don't have any family ties, there's no way to strengthen that. Try to strengthen your other strengths like ties to return, purpose of visit, funds, etc.
GCMS is always a good idea.
You won't get any refund in this case.