why hello sir! Good to hear from ya! short answer- No, the annika head is not 'directly' interchangable with 25th necks. ...BUT it can be moded to fit. they do pop off but they are closer to DC 3 3/4 style figures. My super top-heavy Baroness figure uses the torso and head of annika with joe arms/lower torso- lots of chopping and molding. my Marvel Girl figure uses an annika head that i cut the neck off and dug the hole in the head out until it fit the MU neck.... so, it is not a straight swap for the head- but it can certainly be done with a smidge of effort.
Hey Lo... Do you know if the Spy Lounge figs from guru planet have interchangeable heads with 25th/ME Era Joes? I think I've seen you use the "Annika" body for a custom before, no?