Nobody can "force" you to fill a prescription. In a situation like that, the pharmacist should refuse to fill the prescription that (s)he feels there is a problem with (of course, (s)he should only be refusing to fill prescriptions that there are legitimate problems with....not for reason like she doesn't think the person looks like he needs oxy) If the pharmacist supervisor fires her for not filling problematic prescriptions, than she has reason to go to the board. But I really thinks such a situation is rare, I have never heard of pharmacy supervisors trying to force pharmacists to fill prescriptions that they have problems with them. But yes, reporting a supervisor is a quick way to get put on the "lets get rid of this person" list.
As for the situations in the OP, most people with narcotic prescriptions have them for legitimate purposes. Every situation is different. With #1, I'd probably just sell them the RX--its safe to assume that the doctor had changed their dose shortly after they got the RX, and never bothered to let the pharmacy know (this happens all the time, even with maintenance meds.) Especially if the person does not have a history of seeking early refills. With #2, I would document very well. If the person is repeatedly losing their RX's, then at a certain point I would tell them I was concerned about their health (go into the adverse effects of the medication they are "losing") and tell them I do not feel comfortable filling it. You can also throw in that the law requires you to not fill prescriptions that could be detrimental to someones health. Then offer to give the RX back to them or transfer it (although when transferring the RX, I always make sure the pharmacist there knows the history--many times they will refuse to fill it also, sometimes they just don't care and want any RX....it's their judgement call at that point.) For #3, it depends, what is the RX and how complicated is it. An RX for a Z-pack, sure I'll do that. 10 RX's from the hospital they were discharged from yesterday....I'll send them to the nearest 24hr pharmacy. Even with the quick RX's, it's risky, because they can pull out some archaic insurance card that will take you 20 minutes to figure out how to work. But usually, I don't have a hot date right after work, so its not that big of a deal if I'm 20 minutes late getting out.
Basically, just use your judgement. You can't really have strict rules about always doing this or always refusing to do that, because every situation is going to be different.