Rather than answer point by point,I will explain what I know, have observed and teach.
Modern revolvers do not need an empty chamber. They have a hammer block that prevents the firing pin or cartridge from being stuck by the hammer until the trigger is pulled all the way. The cylinder advances as the trigger is pulled (on double action revolvers- the most common by far) so a round would move into place anyway.
The non-scientific polls I have seen on gun sites split about 90/10 for those who carry with a round chambered vs not chambered. The split is consistent +/- 5% across several sites in the past 5 years or so.
Virtually the only "pro" to carrying without a round in the chamber is the reduced chance of a negligent discharge.
There are several "cons". Life-threatening situations can develop extremely fast. A second can mean the difference between life and death. As pointed out, if a struggle is involved you may only have one free hand to operate your firearm; though there are techniques to rack a slide one handed, it is very difficult. There have been instances where a person under the stress of an attack forget to chamber the round and has suffered injury because they try to fire a gun without a round chambered.
My personal preference is to carry with a round chambered. I teach my classes the same. I promote two points to reduce the risk of negligent discharges.
First I teach positive weapon retention. I dislike off body carry as it is far too easy for a gun carried in a purse, briefcase, etc. to be misplaced, stolen or otherwise fall into unauthorized hands. For holster I recommend a holster with active retention. Even a simple snap strap will keep a gun from falling out. If a person chooses open carry (I discourage that) I recommend using at least a level 2 retention holster.
Second is religious adherence to the rules of safe gun handling. A person's finger should not move to the trigger until the decision to fire is made. That .1 second it takes to move the finger to the trigger is the last chance to rescind the firing decision. Placing the finger on the trigger for any reason besides firing (such as a threat or to "be ready" is criminally reckless.
I hope this answers you questions.