13/ McB:
Another email, 6/13/18 Costello to Cohen: "my friend has communicated to me that he is meeting with his client this evening," and asked Cohen if there's anything he'd like to convey to Trump via Giuliani.
These emails are Costello attempting to establish the Cohen-Costello-Giuliani-Trump backchannel in real time.
Costello just characterizes it as "getting everyone on the same page."