Your first casts will be far from perfect. I wish someone would have told me just how deep the rabbit hole of learning to cast goes!
Appropriate venting is very important. For a part that size I wouldn't screw around with a syringe - it will be too slow for a part that size. Mould release is only necessary in a production environment and things will work fine without it. Talc is a good thing to use though as it will help pull the resin into details - just make sure it's a light dusting, otherwise it will obscure detail and have the opposite result!
As I said in my first paragraph though, manage your expectations. Without vacuum and pressure casting equipment you are not going to get perfect copies. There are definitely techniques to try to get improved results at room pressure, but there will still be an upper limitation.
Oh yeah I can make that....