but... Buffy in canon either couldn't talk about this stuff to Spike, or wouldn't, and either way, it says that for some things, things really close to her heart, she either didn't trust him, or feared his disapproval. (Which is why, I think, she'd never talk to Dawn or Willow about them.)

This is very useful to me. It's a different picture of Buffy than the previous seasons had established - as someone who absolutely can't talk about what's closest to her heart unless it's immediately going down some kind of memory hole, i.e., the Holden incident - but then I guess that's the point, that she'd become a different character by that point, closed and unavailable.

However, her being closed down hardly prevents other characters from talking to each other about her feelings and speculating about them, much as we viewers were. That's the route I probably would've gone with, especially with a houseful of curious newcomers available. But then the writers never asked me. : )