First time long haul flight with baby. I'm taking 18 hour long flight with my 5 and a half month old baby.?

I'm really anxious about it and would love other parents advice. Should I take my stroller (Quinny buzz) with its carseat? Also, online tips tell that I should feed during takeoff and landing to avoid ear pressure. Wouldn;t it be hard with the seatbelt on? Should I just use a pacifier instead? Totally at my wits end thinking about the details regarding cleaning, feeding, making the baby sleep (he is so used to his crib). There is a stoppver for two hours which I think would help. Any advice, tips would be much appreciated from seasoned traveler parents!