Yes, I think it's a good place to vent. (And get feedback.)
I can see how it could be just a miscommunication (or even damage control) on (former) Secondary's part. And I suppose you could tell him you need more communication from (both) him (and Newbie). But you should probably only bother if you think it's worth it. Maybe he could develop better communication skills over time? I don't know.
I wonder if he'd "get it" if he read this particular thread? Might be worth considering.
Anyway, if Newbie is truly just ignoring you, then she must not have any big objections to the (proposed) situation. I suggest paying her no further mind, unless she comes to you with a concern.
I hope things work out in some way shape or form.
Love means never having to say, "Put down that meat cleaver!"