Where is a safety pilot actually necessary?
PIC, under the hood in VMC outside controlled airspace - safety pilot required to maintain lookout to comply with requirements for VFR operations.
PIC, under the hood in IMC (note the tautology) outside controlled airspace - no safety pilot required. Think about it! PIC can fly IFR in IMC perfectly legally on his IMC / IR rating without anyone else in the aircraft.
It would be prudent to obtain a RAS (or whatever it is now called), but not a requirement for the latter situation. The debate has been done on pprune before, and will be again.
Again, whether it is advisable to be flying in IMC if not current (even with a valid rating) is an entirely separate issue.
Completely different if in controlled airspace, of course.
Then the flight would simply be IFR, and again the presence or otherwise of a safety pilot is immaterial - it is now ATC responsibility for separation.
Regarding the logging of time - unless one pilot is an instructor and the other a sudent, then only one pilot can log the time. It doesn't matter which, as long as the time logged is appropriate for the ratings held. A non-IMC/IR rated pilot could not log any IMC time, for example.
DFC does come out with some amazing drivel, btw.
fbw