Re: 3a--Rand could have had someone else provide the instructions--and if so, he would have nothing to reveal under compulsion.

Re: 3b--i could be wrong but i recall Rand telling him to go to the palace under pretenses that were clearly balogna, even to rat man. assuming arguendo that you are right and he did believe his instructions were true, the other factors that he could reveal are more than enough for Graendal to deduce that Rand was in her backyard

Re:3C--Rand could have sent someone with him (ashaman) that he didn not know. the ashaman could turn around after he goes to the palace, come back to rand and tell him it's go-time.

Re: 4b1--of course Rand needed a pretense, but the messenger's knowledge of the facts are what blow a hole in the plan. Rand should have done more to prevent the messenger from observing any facts that can be revealed under compulsion and used to deduce the plan

Re: 4b2--understood but he observed that rand was standing with a gateway to Graendal. this is enough for her.

Re: 4b3--as stated, sending him on foot with others who can report back immediately solves the synchronicity issue

Re: 5b&c--why would she not play it safe and based on the facts, deduce that there was a chance that rand was confirming her location. why would he do that, other than to attack her? i'm sure she would play it safe and get out of there. Moreover, the messenger gave her the location of the gateway so she could be anywhere in the visible vicinity to see what rand was doing and react accordingly.