The Starcraft 2 Campaign Mission Order question has already asked
Will picking missions randomly from the planets available exclude me from doing other missions or will it all just sort itself out?
I am curious what is the most efficient mission order in regard to unit upgrades because whatever unit upgrades at the time of the first play through in a campaign save so what you are stuck with when you replay that mission. Unit upgrades should benefit achievement hunting. Both research and unit purchase upgrades should be considered.
The Evacuation mission, for example, you should upgraded your bunkers before taking on this mission using tier I zerg research to assist in the
Sacrifice Nothing achievement.