1. I would go with laser first and do electrolysis on stragglers. This can be MUCH more cost-efficient. Good package deals can be easy to find depending on where you live. I paid $650 for a package of six treatments (full face and neck), and now I pay $50 per session indefinitely because I previously bought a package.
2. Laser will consume about 15 minutes of your time every four weeks, and that 15 minutes clears all dark hairs from the entire face and neck. But just like electrolysis, it will take a few growth cycles to eliminate the hair, hence the four week between-session wait.
3. It's seriously variable. Some talk about not needing to shave after 6 treatments, but I still have a ridiculous amount of hair left after 11 treatments. My technician says she's got me on a higher setting than almost anyone she's worked on, and she's been in the biz for quite some time. She even does double treatments on my lip for no extra charge and I still have about 50% of the hairs left. For the record, I didn't start out hairy at all. Didn't even have sideburns. I've also heard it's not unusual to go about 20 sessions before lasting results are achieved. I really don't know what to believe.
4. See #3
5. I've seen absolutely no reduction in thickness or distribution of body hair after six months of HRT, and my endo said not to expect any because reports of hair reduction are overblown... I'm not sure I believe that given how many people talk about it. All I know is that I've had none, and the only body hair I have is on my lower arms, hands, lower legs, and feet. HRT has made no dent in this.
6. This is too widely variable based on how your hairs react, what the prices are in your area, etc.
I will say this much though: hair removal pre-HRT was MUCH easier than after. Laser causes your hairs to shrivel up into little dark clumps below the skin, and where those used to grow out in two or three days pre-HRT, they now take about 10 to 11. I have yet to find any makeup that even comes close to covering these, but that might also be because I have really dark hair and really pale skin (it's a strange combo). So for every 10 to 11 days, every four weeks, I want to hide from view.