There is one serious hiking issue that is unique to two people hiking together. This is the accidental passing. You think the other person is ahead when he/she is really behind. Your attempts to catch up only worsen the problem. I have seen this happen once to another couple in Europe, and on the isolated environs of the PCT it is much more serious.
We are serious about safety and attempt to be prepared for any weather that might come up. However, our gear is split. The two of us together have everything we need, but neither carries enough to get through a night on their own without problems. About all we each have is a space blanket and a sleeping bag.
Consequently, we are quite careful not to get accidentally separated. If the person ahead is out of sight of the other, and has to go off the trail, they either leave their poles or their backpack on the trail, so they can't be accidentally passed. Believe me, in my hiking head-down mode, I can miss something two feet off the trail.
This is great for the person trying to catch up. They know they are going the right direction when they see mark A. One more thing we do is when the follower sees a mark, they cross it off, like in B, so if the person ahead ever has to go back looking for the behind person, they will know if that person has been on the trail or not. We do this, but so far, never needed it.
In addition, we set some rules on how far to walk ahead, and how long to wait there, before starting back.You need to be careful not to get separated when it might be too dark to get back together in case of a problem.