If its made for the same scale length it will fit and work fine. You can't really replace the nut without some expensive modifications, but locking nuts work fine, just take the pads and screws off and you shouldn't have a problem.
There is still the possibility of the
neck bolts not lining up though, so it will likely be best to buy a jackson neck, as kramers are hard to come by and ibanez necks are more likely to have the AANJ bolt pattern on them, which means they wouldn't fit.
Alternatively, why not get a neck made? THat way you can get one exactly to your specs and there'll be no problems with getting it to fit or using an alternative nut. Any of the luthiers here should be able to make you one, but I'd say ET guitars are probably the best bet right now, as Jaden seems extremely busy. So does ET for that matter, but slightly less so.