you simply can't play in multi over a LAN, only on the net and not with PJ64.
-It is possible with PJ64K (but for Perfect Dark, it runs out of sync too fast to be able to play)
-For 1964 (current version) you can run Perfect Dark but forget it, the netplay is the worst of all other emus.
-Nemu, hardly runs PD, so, you wont be able to play.
The only thing I can say, wait for the next version of 1964, PJ64 doesn't have any net play system on it.