I don't see that as much different than doing a little "come here" sign with your finger. That's not a question, and you didn't receive verbal consent in reply. You can accomplish the same effect just by doing - approach, but don't continue without a positive response in answer.

In that specific case the verbal aspect isn't so important, no. And the big difference from the context in the advice thread is that I don't have trouble communicating my intent with the body language anyway. But it has felt once or twice that saying something, even something token, has given them more of an opportunity to say something back, and this has led to a non-awkward refusal. I'm not surprised if you find that unconvincing, it's a personal thing and pretty context-specific.

With the breasts, no, I wouldn't explicitly ask in that way. Hands go on body, hands caress slowly toward breasts. Pay attention to response. Another way is to look where you intend the hands to go, and go there. Perhaps a comment on the breasts first.

"Can I take these off?" Probably more like "Let's take these off." Which again, is more like what you generally do. You don't say "will you come here?", you say "come here".

For me it really depends on my model of what I think they want. Like, assume I'm pretty sure that there'll be a line somewhere. Obviously, the right thing to do isn't just "escalate until they give an explicit 'no' (either verbally, or by moving my hand away)". But even if you just proceed cautiously and keep gauging their response, they're likely to spend a lot of the time thinking about when/whether you're going to push past where they're comfortable, and steeling themselves to give that no when it happens. Especially with girls, most will have had more than a few negative experiences with pushy guys.

I mean, I'm not exactly timid or inexperienced, but I still hate it when a guy just grabs a condom and rips it open, if that makes me say "no".