Nice summary on Chandra - my feelings were the same as you layed out here. I actually messed around with some of the choices for the Abby / Chandra scene initially trying to find the route where I could tell Abby I was just interested in hopping in the shower with Chandra while she waited in the living room...but as you noted, that never comes, it's forced down your throat no matter what if you want time with Chandra. This setup was terrible. It doesn't take your previously declared choices / preferences into account. I like Abby, but I'm not interested in her being part of the relationship with Chandra - never have been and my choices have been clear on that throughout the game.
The scene as a sex scene, as you noted, was lit, but for players who have just been interested in a solo route with Chandra, it was not well-written at all. The pre-hotel setup was idiotic and a phone call from the MC to Chandra would have made much more sense. I asked earlier in the thread the same question you covered here in your third bit, about setting up an ending - we haven't seen that choice to setup yet like we did for Victoria, Katie, and Gloria in Ch12. Why not? Definitely want the wholesome / solo ending if there will be one, but I'm increasingly losing any faith that it's coming and heavily leaning toward not buying Book 2 of the game on Steam (Steam purchases are how I support the devs in most cases if I feel they deserve it, and on rare occasions I'll support on Patreon as well). There's still time to get back on course, but at this point I'll believe it when I see it.