For additional Vampire features, I think you forgot Kindred senses which allows vampires to operate easily in the dark as well as detect blood and heartbeats easily. They get to add Blood Potency to rolls that may use their kindred senses(like determining if someone is lying while you are close enough to hear their heartbeat). Lastly, Kindred senses allows for the Taste of Blood roll to gain information from blood and vitae you drink and the ability to track people by scent if you've fed on them before(mortal only) One minor omission is that making ghouls requires an act of will by a vampire(1 willpower) when feeding the mortal your vitae the first time. So drinking blood doesn't give you powers unless a vampire wants it to.
Actually I don't think your clan bane mitigate detachment, all vampires can choose bane (there's a list on the book, but are things like risk frenzy on hearing bells and etc) and the bane make him don't risk breaking point on the price, you can only get 3 of them in total (unless you have a coil) and for each bane you take to overcome a specific detachment, you take -1 on further detachments. The Tenebrous Curse, basically, makes you take a bane right way, enforcing mekhets as a clan of really different people, besides that, you have 1 less bane to take for resist detachment specific detachment you want. And I believe this is what the tenebrous curse means, the bane you take here, don't make you resist to any attachment, making mekhet only have 2 banes to overcome detachment
About the Disciplines: The text of the core book is a little bit misleading. I believe you are supposed to pick three different Disciplines (with one dot each) as mentioned on the official VTR 2e character sheet.
When you fail a detachment roll you can take a Bane to prevent that same breaking point from ever risking detachment ever again. This gives you a permanent stacking -1 penalty on all other detachment rolls. Tenebrous Curse gives you a Bane at Humanity 6 that counts towards your normal limit of 3 banes. It also makes your effective Humanity worse for all Banes you possess, including the natural Banes all vampire's share. Clan Banes dont mitigate detachment in any way, though, including the Mekhet's Tenebrous Curse. The only Banes that help with that are the voluntary banes you take as described above.
It was fun! I did similar for Trinity Continuum, but honestly I do tend to favor potent in theme abilities. I ended that Stream with 5 dots in two Attributes 😬. So while on the surface this character may seem pretty unoptimized, I think if Theo took it to the table he’d seem pretty formidable.
Risking a Humanity break because you didn't die from your injuries is a really stupid mechanic. Like, I get the theme they were trying to go for with that, but I'm not happy with it.
