Be clear and be firm that you want a physiological third stage. Make sure your birth partner is completely on the same page as you and reiterates it to the midwife/Ob as needed. Write it up into your birth plan. Discuss it prior to the birth with your Ob/midwives. Do what you can to make sure they know and respect your wishes. Sometimes synto is necessary (PPH etc), but if everything has gone well, no major blood loss etc then there's no reason why you need it. My Ob for DS2 had no dramas with me having a physiological third stage. Same with midwives for DS3.

Re: first breastfeed. DS1 wasn't particularly interested, so sometimes it may take bub a little while to get its head (mouth?) around, but as we did with DS1, I put DS2 and DS3 near my breast and nipple and they have a root around and latched on pretty well straight away. All bubs are different. The midwives can help you though, so don't hesitate to ask for their assistance to get bub attached if you're unsure.