Not really. The Seanchan already hold the two major port cities, and Rand has given up on a third, Bandar Eban. Illian is protected from a seaborne attack by its marshes. Tear can't be attacked by sea because of the Fingers of the Dragon. The arrival of a fleet to Tear would be known about half a day before the first ships arrive to the city, and much of the fleet would still be stuck in the Fingers. And that's if the Seanchan ships can sail the paths in the Fingers. They are bigger than Sea Folk ships. That leaves only Mayene.

But with the Empire in civil war and TG about to start, how relevant any of this will be? No new ships will come to Tuon's help, or at least it's very unlikely, unless loyalists decide to leave the Empire and join the legitimate heir (that is, if Semirhage hasn't spread the rumour in Seanchan that the Return has failed and Tuon is dead, which she may well have...). They won't come en masse anyway. The fleet for the Return was many many years in preparation, and is in the Westlands - what's left of it...

It would be relevant in future years if the Seanchan conquest isn't abandonned during TG (but that won't be Rand's problem then), but it's not very likely to be relevant to the rest of the series, especially that the Seanchan war fleet in the Westlands has been seriously reduced already by the battle at Ebou Dar. What they have left is in Tanchico and Cantorin. The most Rand might do now is have the Sea Folk blockade all the Seanchan-held harbours to tie them down where they are (a bit pointless - it's by land they are a threat, not sea), or destroy the ships, if upon his return from DM he returns to his notions of fighting the Seanchan. By the end of TGS, he rather intended to ignore them because time ran out for that and he gave orders to mobilize everyone for TG instead, then in his darkest hour he thought to destroy the Seanchan leadership himself with the CK. Upon his return from DM and the way he sees things in a new light, he's more likely to contemplate other solutions than war.... or to ignore the Seanchan problem for the moment, to focus on the Shadow. It's only when he learns of the attack on TV, of the theft of the Travelling weave, or if they attack the BT that Rand would make the Seanchan a priority again. Right now Rand expects the Seanchan in his back during TG, and thought he'd have to live with that. He doesn't yet know they've made trouble in the north too. By the time he does, TG may already have started.

All in all, if there are naval battles coming, it's more likely the Sea Folk themselves, not Rand, will decide to liberate their occupied Islands (one archipelago is occupied) and finish what they started in Ebou Dar, ie: cripple the Seanchan's seafaring capabilities. They didn't think it was Rand's business then, and they wouldn't either now - and their relief mission is over now (and a lot of their fleet is now close to Cantorin, as it happens). The Seanchan would stop being a threat to their own interests then. It's indeed curious Jordan included two big naval powers who are enemies, with no plan for a big clash at the end or something.


A Sea Folk-Seanchan clash could happen, just like Rand doesn't have any control at the moment on what happens between Seanchan and White Tower. It would keep the Seanchan distracted from the north for a while. Fortuona right now seems intent on bringing Rand to his knee not by confronting him but by attacking those she believes to be his allies, like the WT and maybe the BT next (Yulan had two battle maps in KOD, one was revealed then as TV, the second one is still a mystery. It seems very likely Brandon ignored that second map for now because they chose to split the books, and so it gave too much away too soon, as the second battle will likely happen in TOM. It was always a bit curious that the Seanchan focussed everything on the WT in TGS and ignored the Asha'man. This second map in KOD was most likely a map of Caemlyn and the BT a few leagues south) and this could mean the Seanchan too might be involved in the "big event that starts TG" at the end of TOM, that will reunite all the main cast. They may come to raid the BT, only to discover "the Light" is are already fighting it (or Caemlyn is under attack from the BT)...