It's clear that Egwene has to send very capable and experienced AS, whom she can definitely trust. Therefore I suggest that the embassy will consist of Siuan (the Blue), Leane (the Green) and Meidani (the Gray as leader). To send the former Amyrlin and her Keeper would honor Rand (besides, Leane is a charming woman.. ). Egwene also noted how successful Meidani must have been in the past, when she visited her rooms in TGS, ch.12, and saw the many gifts Meidani got during her work as a mediator. Plus, via TAR Egwene could stay in contact with Siuan.

I think this combination of the embassy would makes plot-wise some sense, too. One can expect that the Warders of the AS I mentioned and maybe some additonal soldiers accompany the embassy as an honor guard. This would allow the opportunity to bind yet another Great Captain to Rand, namely Bryne. Plus, some people speculated that Tam might fall in love with Leane. This could soon happen, if Leane is part of the embassy. Finally, once Moiraine is rescued, and if there is a great reunion of the most important characters in Caemlyn, there could be a very touching scene of Siuan seeing her oldest friend Moiraine again, whom she considered to be dead.