So I'm new to boxing, but I've decided that I want to 5-box a mixed group when Classic is released to give myself maximum gold farming options upon hitting 60 without having to separately level "farm" toons such as a mage or hunter. (I plan on maining a warrior)

I didn't want to add this post to the Classic mega-thread because my questions are not specific to Classic but would rather apply to any leveling scenario.
From reading many many leveling guides, it appears to be generally accepted that the fastest way to level is some combination of questing+grinding.

My big overarching concern is receiving false botting reports from ignorant players, and subsequently receiving false bans from ignorant GMs. I see that this is a thing that happens, and even if they might be overturned, I do not want to lose days of early-server leveling time having to fool with such nonsense. Even in the limited amount of low-level 5-boxing I've done in retail wow, I've been on the receiving end of whispers like "well that's not obvious at all lol" and so forth.

As a result, I feel like I want to avoid people as much as possible while boxing from 1-60 in Classic. That would seem to take questing off the table unless I'm able to do so in extreme off-peak hours. That leaves grinding as my primary leveling method.

My actual questions:
#1 - How much slower might it be to grind from 1-60 compared to questing+grind?

#2 - Are there any good instance grinds? I'm very interested in such spots as they would allow me to level in complete isolation with zero player interaction. For example, would grinding the non-elites in BRD be efficient at 52+? Any other instance grinds that would be comparable to open world grinds? Even partial instance grinds, resetting as necessary?

#3 - Am I just worrying way too much about getting reported and/or banned?

Thanks in advance!