I finally got the mouse targeting working. Thanks for all of the information to create the building blocks for it.
I first set a boolean for “Lock-on Mode” that toggles when I press the button.
Then when Lock-on mode is started, I get the targeting sockets I placed in the skeletal mesh with this function:
Then when in Lock-on Mode, switch the mouse controls from controlling the camera to comparing distance from cursor to each of the sockets when you move it.
This method compares the angle from cursor to each socket:
Though in the future, I should probably switch from projecting the cursor position to 3D space, to projecting the 3D space locations of the sockets to their positions on screen to compare distance from cursor.