Baby born to tier 5 visa holder and British citizen

Hi,

hoping someone can help on this one my partner who is a British citizen is pregnant with my child, i am currently on a tier 5 TW visa from Australia I have been advised that applying for a FLR-FP visa is the way to go however i have a few questions.

1. for my application i need a cover letter, what should be included on the letter itself, if anyone has examples of a cover letter i can send that would be very helpful!

2. we are not getting married yet and we have been together for about 18 months at this point will this be a large hindrance

3. i was advised that if i apply closer to the end of my current VISA i will be legally allowed to stay and work whilst my application is pending, and if it is declined i will have the right to appeal the decision, is this the case?