Should we carry walkie-talkies?
Two-way radios are generally more hassle than they're worth, with the exception of long aid climbs, where certain information needs to be relayed to the belayer.
When multi-pitch climbing, there's really only one morsel of communication that should occur between the leader and follower and that's a signal as to when the leader is off belay.
If you're out of earshot and it's unclear what's going on, the leader can tug on the rope to communicate this to the belayer. The best signal here is for the leader to simply make several tugs to indicate that they're off belay. Don't try to count tugs or shout over the wind. Just yank on the rope a lot.
When the rope comes tight onto the follower, they should wait a few moments and then unclip their tether and begin climbing.
An experienced second should know what's going on at the anchor by reading the movement in the rope and imagining the leader's actions.
Walkie-talkies, tempting as they can be, sometimes fail. Without another rehearsed system, the climbing party is in trouble. Batteries can die, interference can occur, or someone else might be on your frequency.
If you want to haul extra weight up the rock, choose another form of insurance: like extra water, an emergency bivy, or a rain jacket.