Hey Sam,
Thanks for the questions and welcome to the Forum! I can't claim specific expertise on either of those questions, so let me weigh in with my thoughts and see if someone else has an opinion as well (I'll also revisit this if/as I learn more about these particular concerns).
To your first question about the college interruption, I don't think that counts. You were still a high school student after all, meaning college for you hadn't technically begun, or at least not in the traditional, full-time sense, and that's really what they care about as I understand it. They're looking to see if, for some reason, once you began attending college or university you stepped away from it for any meaningful amount of time (more than a semester off, say). That's a curious event, and schools want to ensure that "curious" isn't actually something more worrisome, like a prison stint or something
(or, more likely, a reflection of a pattern of spotty commitment, in much the same way they look askance at an applicant with 9 different undergrad majors).
So I think a "No" there is safe. Of course, if answering "Yes" then allows for a recounting of exactly what happened—like an "If 'yes,' please explain below:"—then there's no harm in answering in the affirmative and telling them what you just told us.
To your second, that's a little trickier. A good rule of thumb for applications, and really I can't over-stress this, is BE HONEST. Seriously. You don't want to risk trying to hide or obscure information, only to have it come to light later and make you look anything less than truthful and trustworthy. Save the deceptions for your legal career (I kid, I kid).
Schools deal with multi-school applicants nonstop. It's incredibly common, and they know better than to expect a bunch of one-school,
their-school, candidates. Would they prefer that (or something on the light side, like fewer than four or five schools)? Maybe. Other schools are competition, after all, and the more competition, the lower your chances of winning...in this case securing your attendance. That's the entire philosophy behind early decision. But if you're qualified and express genuine interest then I'd say the risk of being dishonest when explicitly asked grossly outweighs the risk of non-acceptance just because you're not exactly Mr. Monogamous
Still, others may feel differently or have more to add, in which case fire away!