That Electra is usually parked in cargo, but for some reason it was on stand 9, it usually doesnt take off during the day.. so it must have been tech or something like that.. unless it was chartered for an extra cargo flight
Gate 22, its not a temporary pier, but it does look like it from the inside and outside.. there is also talk of extending it further down into the cargo end, and create a new cargo apron... but plans no doubt have changed... the actual desk for tickets to be scanned is in the same block as gates 21-27, but its 1 hell of a walk... usually A/C are put there if they wont be moving until later that day, although the Jet2 that you saw was more than likely their cargo plane that does mail runs
was defo a day which saw a wide variety of a/c at BFS.. but like BelHold says if you want to see different a/c then get up earlier or later in the evening..