I would suggest:
b. Would you like to purchase priority boarding? (when booking)
g. Would you like an aisle seat or a window seat? (when checking in online or at the airport)
a. Do you have any bags to check in? (at the check-in desk)
c. Do you have any liquids, gels, or pastes? (when going through security)
i. We have held your bag back for further screening (at security)
e. All passengers on flight MX937 to Hamburg, please proceed to gate 14a. (in the departure area)
d. Please present your boarding pass and have your passport open at the relevant page. (just before boarding the plane)
f. Please keep your seatbelts fastened until the seatbelt sign above your head has been switched off. (on the plane)
h. Do you have anything to declare? (when going through customs at the destination airport).
BUT the exact order does depend on the airline and airport. Are there a lot of differences between my ordering and yours?
Which of these instructions would you be more likely to hear, and which would you be more likely to read (on a notice or on the airline website)?