Your birth name will always be stronger then your witch name in the aspects of it being connected to you. Primarily because of the time in which the name was given to you, and because of how long it has been associated with you. You also greatly connected yourself with that name, and many others have connected you with that name, and because of all of these things your birth name is a powerfully connected taglock.
Your witch name does not have this amount of connection to you, but it will still have connection, so yes it’s still can be used as a taglock, but it will be a much weaker taglock. Spirits would be able to easily figure out your birth name by investigating your life, but every small prevention helps, and it would be mostly for spirits that you are conjuring, and sending away that would not have access to your abode, or other aspects of your life.
The dead name still does have power over trans individuals, though it does have less power because of how much it has been excommunicated, but since the dead name is a birth name it still does have a lot of power over the individual even though it is more seen in a negative light. It’s power would be even higher if people refuse to use your new name, or or greatly associate you with your dead name.
Your chosen name is very powerful, because it is a name that is now greatly associated with you, and is the name that you communicate all of your presents from. It is also greatly personal to you because you went through the act of choosing it to represent you, and your energies in all aspects of your life.
Your witch name would be the weakest one still for taglock usage, and would protect you the best. Your chosen name, and dead name would most likely be quite equal, but with your dead name lagging behind in their taglock power, because of the different aspects, and elements that they both have, and their relationships to you, and both of these names could be used in order to get to you through cursing, or spell casting. Though if a person was going to go through the process of cursing you they would most likely want your dead name over your chosen name, because this name has already built up a negative connotation with you, and your being, and these aspects, and understandings would be able to be brought into the curse. Though if they were doing something more positive with a taglock they would want to use your chosen name.