Crosscheck basically means to have something checked by another person altogether.
An example of this would be working through pre-flight procedures, and the captain may check that the autopilot is armed, and then the co-pilot would also check that it is armed. It's basically like double checking, but with another person instead of one person.
I havn't heard of 'allcall' before, but the Google 'define' funtion mentions that it allows the person to talk to all intercom speakers. I am unsure as to whether this is correct in aviation terms, hopefully another member will be in the know.
I think you mean "doors armed and crosschecked" or after landing at the gate "doors to manual and crosschecked"...missus was a hostie! Anyway doors on departure are armed ie evac slides armed so if you open the door it deploys. On arrival doors are set to manual (unarmed) so when doors are opened the slide does not deploy. Crosschecked by the crew member on the opposite side, verified. Same goes on the flight deck all is crosschecked...I will calculate TO performance and Capt will crosscheck.