Yes linear actuators would probably be expensive and are not usually back driveable.
Stepper motors would work but seems over kill if your not wanting to say half open the door etc ( this could still be done with a dc motor) also you should still fit endstops to prevent accidents.
DC motor probably the cheapest and easiest to set up, would need end stops and could use timing to give part opening etc or even fit with a encoder to report position.
Really the choice is yours I just recommend a DC motor.
Check out this where they use an old windscreen wiper motor.