Enlarging the bulb and socket shows the labelling
Christiana 9000 and the internet seems to have various hits on that. As well as a plethora of "you know, maybe, maybe not, ha-ha, if we drop things from your search term" hits. Both bulbs and sockets seems to be the definition of inexpensive. Of course, having to replace the sockets would make the overall job more involved than just working the bulbs free and putting in new ones.
Definitely pull out, straight out. If you wiggle it/one to free up any stickiness/reluctance, do it left-right so to speak, on its axis that is parallel to the plane of the plate they are mounted on. Also, remember counter-torque and adequately hold the socket itself still as you work the bulb.
Might also point out that the wires are barely connected, which isn't a thing if you did that yourself before taking the photo. But if they were like that, you'd probably want to improve it to some extent. At least clean the connectors and wire ends before putting them back in the incredibly sad way they are now. But, you know, no preaching here. If they lasted a long, long time prior to this, they may do so again, sad connection or not, and the voltage is in the "safe" zone, so...
A tighter connection, even some solder, might make the next set of bulbs last longer and perform better while doing so.