I'm going to push back a little because society needs to discuss this more rationally. Gaiman might believe he is innocent and he is, until such time he is proven guilty in a court of law. Whether or not these things happened or not is outside of our ambit as a society to decide. We do not have all the information and we must be very careful of deciding one way or the other because we are underinformed. Whether or not you choose to believe Gaiman is neither here nor there - nor is it my job to decide whether he should be believed or not. Courts are the place for these things to be settled. We've been here before with Amber Heard and it set the feminist push back a long way.
When it comes to BDSM, this does blur the lines... but as a general rule, those who engage in BDSM are usually more conscious of consent than those who don't. You make some good points about rules and explicit discussion - but you have inferred that he didn't have the necessary conversations, that there was no safe word - we do not know this. We can infer this, but we don't know it.
I'm with you on enthusiastic consent - more clarity is needed across society.
I'll respond to your points:
1. No means no. BDSM requires a safe word.
2. It's nobody's business who gets to date who. When two adults enter into a consensual relationship that's the end of it. Everything else is simply moral grandstanding and subjective fuckaboutery. It's a matter of what YOU think as an individual. I don't think its my place to tell any adults who they can and cannot date. The law is fine.
3. Again. Two adults consent. That's fine. They need to be aware of the conditions of their consent and they need to be aware of the restrictions which may exist in their workplace. Adults be adults, the power dynamic is easily understood by all involved.
4. Once again. If your fans are adults and if they consent, what the hell has employment got to do with anything? This is moral grandstanding dressed up as concern. Dynamics should be considered BUT that applies to everyone. If everyone is an adult, everyone can consider what they get out of the experience. Not my place (or anyone else's) to make a judgement call on what two adults choose to do in the privacy of their own lives.
5. On this we agree.
The problem with your definition of coercion is that it can be retrospectively applied - and the way you've described it, almost everything counts as sexual coercion. Romantic gift or sexual coercion? It depends on the inner states and thoughts of the individuals involved and that's not how we do laws and makes a mess of the more complicated areas of consent.
Can we reverse this definition and get a counter intuitive result. This girl keeps having sex with me, so she wants me to buy her things. Is this now sexual coercion working towards robbery? I'd argue no. I'd even go as far as to say that adults should be aware of their inner thoughts and adjust entirely, have adult conversations about what and what is not expected. For that reason, I'm not convinced you've given a clear example of coercion here. I don't think you've adequately defined it and I don't think you have all the information at your disposal to b able to draw a conclusion.
We wait for the courts.