People never stop fighting about religion, do they? I have a chequered religious past and my beliefs have changed, some might say dramatically, over the years. I still haven't come to a standstill in thinking about God and his alternatives and I would never challenge anyone else's beliefs (political, yes, but spiritual, no). However, my beliefs about organised religion are now pretty much set in concrete. I think that, on the whole, religious organisations - often in spite of their best intentions - have done more harm than good in the world. A very dear lady - a nun, now dead, sadly - once said to me, "To do good in the world, you must hold your beliefs in a very loose grip." I can't think of a better mantra for living in this combative world full of people convinced that only THEY know the Right Things and they feel justified in trying to destroy anyone who thinks otherwise.
You must do what you feel you want to do. If you don't want that vicar to "take charge" of your funeral, then leave clear instructions laying out what you DO want to whoever is going to be arranging it. My DH and I have done exactly that and have gained great peace of mind through doing it.