If you wait for some communication from Manila you will be waiting for a decade. Everything is posted online. Find, read and follow. The quicker you do the quicker it will be over
If you wait for communication from the embassy you will be waiting for years. Everything you need to do is posted online on the embassy website. Get movin
You cannot file for visas for your fiance's family members, they file for visas for themselves. Nothing a USC can do to influence the decision including any sort of sponsorship.
I submitted boarding passes for my inbound flight, passport entry stamp, two boarding passes from an internal domestic flight we took. That's about it. Just have to think what is available to you.
Generally speaking, self sponsorship is not widely considered as an option. It has been reported on occasion that it can be done in the UK but have never heard it as a possibility in Turkey
Also, not all airlines have interline agreements for automatic baggage transfer and if you have this situation you will need to collect your luggage (which is after border control) and recheck. This would cause someone to enter the country as well.