Questions about Tyrek Lannister and Ermesande Hayford

"In case of the Faith of the Seven, a septon presides over the ceremony, which involves prayers, vows, and singing. The bride and groom speak the words 'With this kiss I pledge my love' potentially followed with an additional '… and take you for my lord and husband' and '…and take you for my lady and wife' by the bride and groom respectively, after which the septon will declare them to be man and wife, stating they are "one flesh, one heart, one soul, now and forever'"

- ASOIAF Wiki

During the marriage between Tyrion and Sansa, much emphasis put on Sansa saying the vows. This indicates that the words themselves are necessary or at least important for a legitimized marriage. However, in the case of Tyrek Lannister and Ermesande Hayford's marriage, one party wasn't able to say the words because she is an infant. This makes me wonder how the marriage occurred and was legitimized.

Assuming the marriage fully legitimized, what is going to happen now that Tyrek is presumed to be dead after his disappearance? How akward would it be if Tyrek shows up later, but Ermesande was already married off to someone else.

If the marriage is deemed later on to be illegitimate, then what are the implications if any?