Keep in mind this is just one persons opinion in response to your questions. It's also worth noting that, by comparison to the vast majority of users here, I have very little experience. I've had very few interactions with the public while carrying, and what I have had has all been positive. I've also never spoken to LEO while carrying, positive or otherwise. Now, all that being said...
1) It depends who you are referring to. Co-workers it's probably a good idea just because it's possible your company has a policy against its employees carrying. Unless I missed it, you didn't mention if you had looked into that yet. Customers will probably be a mixed bag. Businesses and private citizens will likely all have their own policies and/or opinions. I don't know if signage/policy carries force of law in your area, something to look into. Really though, the answer to this regarding anyone else you interact with outside of work is probably more dependent on what makes you feel more comfortable carrying in the beginning.
2) In general, it's never a good idea to speak to the police outside of reporting a crime to them. A better idea is to find a good Pro-2A attorney in your area and pick their brain. It may cost a few bucks, but if you feel you need the advice, it's better to take it from someone who actually knows and understands law and how to read it. Good questions to ask include, but aren't limited to, how they would interpret and spin certain situations, that could go down while carrying a firearm, in a court setting. If you're into the gun related channels on youtube, TheYankeeMarshal did a video presenting some information he got while speaking to lawyers about self defense shootings. One lawyer noted that painting your firearm a color that might make it look fake, like all blue or red or something similar, could be spun in court to make it look as if you were trying to trick people into thinking it wasn't a real gun so they would be more likely to test you and give you an opportunity to fire. Again, take it from me with a grain of salt, I'm certainly no lawyer, but those would be the folks to talk to.
3) This question is probably better directed specifically at those in your states sub-forum. Here in VA, the reactions from the general public in my experience are largely non-existant or positive. As I said, I've yet to have a negative interaction, or even notice any dirty looks. Your mileage will vary, though. I would like to reiterate my earlier point about carrying while working. Given your profession, you'll be spending a lot of time entering other peoples property. You should find out how that effects your right to carry in your state.
4) Once you decide on the pistol you intend to buy, or even narrow it down to a few, head to the holster section of your local gun store. Ask them if it's alright for you to pop open a few of the plastic boxes for the different types of holsters and try them on. Figure out what's most comfortable to you. I like OWB hip holsters. My favorite so far has been the Blackhawk! Serpa II's with the paddle clips. It offers a good amount of comfort and good retention. Others swear by leather. This is something you'll only figure out by getting hands on.
5) This one I'm not sure about in your area, another question for your states sub-forum. I feel like something that makes you more likely to hit an INTENDED target can only be a good thing. Bold added for emphasis, since pulling the trigger in a self defense situation should only happen after a clear threat to life has presented itself, thus the trigger pull would be intentional. I would recommend practicing with it enough to know basically where the bullet is actually going to go in relation to where the laser is painting.
6) Be ready for the possibility of extra attention because you're carrying. It may happen, it may not. Do your best to learn the subject in and out, including current laws, changes that may come about in the future, and maybe even how they have changed from the past. Most interactions you experience due to you carrying are opportunities to educate. You say you don't want to lose your rights or life because of negligent research. Realize that both of those depend not only on your own research and the passing on of that information to others, but also sometimes to previous lessons people may have learned from others. You might have a positive interaction with someone because the last person they saw open carrying was a polite, courteous individual who took the time to educate them. Or, you could have someone call in a MWAG on you because the last OC'er that Joe Public at the deli counter in WalMart saw was a jerk. In either scenario, knowing well your rights and the local laws/ordinances will help you. Making up your own information cards to keep around and hand out isn't a bad idea either.
7) This forum holds a wealth of knowledge, experience and opinions. Use it! A lot of places organize regular OC get togethers. It's a great way to meet people with similar interests and beliefs, and to pick their brains. If that's something that interests you but your area doesn't offer it currently, you can always start your own. Build it, and they will come, and all that.
Know the prohibited places in your state. Make sure you don't carry in those places. Google is your friend on this one when it comes to restaurant and department store chains.
I'm not sure if this applies to your state, but in MI open carry is legal until you get in your car unless you have a CPL. With out it you have to unholster, unload and lock it up before you hop in the car. Things like that are usually hidden in the wording of your states laws, and aren't necessarily obvious on the first read. Hopefully someone from your state with more knowledge can hit on this point later.
That Pro-2A attorney I mentioned before? Put their number on your speed dial, and keep their business card in your wallet. That way, if a negative situation goes from bad to worse, you have someone to turn to, and someone you can insist the police let you speak to before you have a change to open your mouth and give them a reason (real or imagined) to cuff and stuff you. Voice or video recorders are a great idea, too.
So there it is, hope this helps you out and gives you some things to consider. I'm sure I missed a bunch of stuff, probably worded some things poorly and may even be flat out wrong on some of it. I know someone will correct me if that's the case, though. That's the great part about this forum. So, welcome to OCDO from VA. Carry on!