Close to zero chance of interlining with separate ticket for scoot. There are a reason why SQ is selling codeshare on scoot.

scoot check in close 60 mins before departure.
so you only have 30 mins from arrival to go through immigration, collect luggage and went to the departure counter to check in.

refer to below.

https://www.flyertalk.com/forum/36211718-post191.html