OCI process is actually quite simple, it is their execution that makes it v complicated! trying to answer your points below.
1) Filled in OCI form, and downloaded pdf. It already has picture & thumb impression which was digitally uploaded. Do i paste a physical photo on top of this photo? NO. JUST A PRINT OF THE FORM.
2) OCI pdf form has "declaration" section with signature of the applicant. Does my baby need to put thumb impression thr? YES. APPLICANT'S SIGN/TI AND THEN IN THE 2ND SECTION ON THE SAME PAGE - BOTH PARENTS' SIGNATURES. PL DON'T FORGET TO INCLUDE THE NOC, SIGNED BY BOTH PARENTS, AND 1 PHOTO EACH OF BOTH PARENTS - AS PER OCI SPECS.
3) How do I pay the courier charges online? This link
https://www.blsindia-canada.com/toronto-jurisdiction/postalbls.php does not work. CALL N PAY.
4) If I am write we have to send 2 demand drafts. One is $376 and other is $1.7? APPLYING THRU COURIER? YES, OTHERWISE A 376 DRAFT AND REMAINING YOU PAY ON THE SPOT.
5) If i have to submit in person, there is literally no available appointment online. YOU CAN WALK IN, OR YOU CAN TRY THE APPOINTMENT PORTAL AT DIFFERENT TIMES - THEY RELEASE NEW APPOINTMENTS AND ALSO PEOPLE CANCEL THEIRS FROM TIME TO TIME. IF SUBMITTING IN PERSON, BOTH PARENTS NEED TO VISIT.
6) While sending by post, do i need to send original passport as per documents?
https://www.blsindia-canada.com/toronto-jurisdiction/pdf/Checklist_Information_Booklet_for_OCI_2jun22NN.pdf