Ambraea needs to build alliances, and I think that Houses Cathak and Peleps are two of her best bets. House Cathak is one of the three military houses, and will only grow stronger after the fall of the Tepet legions. House Peleps practically controls the navy. Any factions that form after the Empress disappears will seek the favor of these two houses.
The problem with this is, as two such desirable and well positioned grand houses, they have their pick of allies following tepets fall and Ambraea's mothers disappearance, making Ambraea one young sorceress in a sea of potential allies vying for influence and connection with them. Worst, she is someone only beginning to build such connections, leaving her with less influence, sway, and most importantly, trust than those who have long courted them.
House V'neef or sesus on the other hand, we have a long established connection to and multiple introductions to members both significant and not. While a marriage to Cathak or Peleps would only be a tentative step into establishing familiarity with them, with Vneef or sesus it's more of a finalization of long cultivated allies. Ambraea would be more established in V'neef than her father's family, while sesus would be on the same level.
House V'neef may be in a strong position now, but it's going to be in a pretty precarious situation when the Empress is gone. It only recently gained control of the merchant fleets and House Peleps really wants them back. Peleps can't do anything about that now, but they'd be a powerful enemy in a civil war. V'neef, as the Empress's current favored daughter, is probably also going to be seen as a major threat by anyone with a claim on the throne.
V'neefs vulnerability, combined with Ambraea's influence and resources, actually make it a more appealing option. V'neef survives the coming civil war without Ambraea afterall. With Ambraea, her presumably expanded Hearth, and possible allies through Ambraea's Burano connection, V'neef has a chance to come out of the civil war stronger than otherwise, and Ambraea can establish herself more strongly in a grand house with much to lose that she's already established herself with than a house that has less need of her and neither trusts or appreciates her as much. It's bit more of a gamble, but there all gambles.
That all said, I mainly chose Isri and Vemi because I think either one would be a cute husband for Ambraea.
More cute than sorcery nerds Ambraea and Darting Fish sailing around to collect rare spell components, Darting Fish forced to play amicable husband to Ambraea's stoic Snake Witch?
Sesus is more funny than cute I suppose. Amiti is the cute in that situation. Cutely imposing on her cousin who must now pull off the social wheeling and dealing of a spiral academy graduate and Sesus family member while his Spirit Witch wife and Necromancer cousin do ominous sorcerer things that occasionally involve the denizens of the shadow lands or spirits which are "Only moderately dangerous" and of course, playing host to rare visits from a juvenile earth dragon spirit.
When I really think on it, is anyone but a sesus husband prepared to deal with the kind of shady sorcerous nonsense potential Hearth Bondmates Amiti, Ambraea, and Maia could get up to? It feels like poor pliable Cathak would find himself quickly in over his head, though I suppose the others would manage with time to prepare.
What makes this question complicated is that what Ambraea thinks she will be doing in the next 10 years is likely going to be a bit different from what she will actually be doing.
Well I think it's safe to say that Ambraea will be a sorceress if she is still alive then and do some kind of sorceress related things, so there is a basis of context we can apply. Also, given her friend circle, well, I think it's safe to say that between her two closest friends, the ones she is most protective of, and there less than societally acceptable inclinations, Ambraea is going to be doing damage control. Decades and decades of damage control.