I had a quite specific birth plan for DD, but with the caveat in every paragraph 'unless my baby is at risk' and told my midwife that although my birth plan was my preference, if I changed my mind or absolutely needed intervention I wasn't going to stop them :) I honestly believe because I went into the whole thing so relaxed with a what will be, will be attitude it made it a very good experience for us.
Wrt bf I wanted to and I tried immensely hard, but DD had an op at 5 days old for a severe tongue and lip tie, which hindered us significantly and at 7 days she just couldn't figure out how to latch so I expressed when she was asleep, fed by bottle when she was awake and drove us both into a stressful day or two, so DH just upped and got some formula and all of a sudden she could be in the same room as me without screaming the house down! It didn't work out for us, but she's flipping bright as a button as bar the odd snotty nose, never ill so totally the right decision for us :)