1. Rawat is not a charlatan because he believes in his delusions

Well actually, the definition of "charlatan" is basically a Quack.  It doesn't really get into whether the Quack believes that's what he is  or not. 

Rawat is a charlatan for a number of reasons, depending on what he was claiming at the time.  He can't show you God, he isn't the source of happiness, and he doesn't provide either peace or happiness that people wouldn't have without him.  So, he is a charlatan and that definition fits.

2. Brainwashing or thought reform is not an appropriate term to explain conversion

I agree with you that "brainwashing" is not an appropriate term because it implies something done against your will.  As has been pointed out to you numerous times, people become premies willingly because they see something they think they want.  In that process, they make compromises and allow themselves to engage in "thought reform" which I believe is, in fact, an  appropriate term, if you mean that it is done internally, like self-censorship.  They make a deal.  In return for getting what they want, they will reform their thoughts and not look at the cult and its teachings objectively in any sense.  This is continually reinforced by the cult that they should do this, before after they get knowledge, but this is not "brainwashing" because it isn't coerced in the usual sense of that term.

What a cult member does (and what actually makes them a cult member), is to engage in self-censorship of thoughts, and that really IS thought reform.  They stop doubting or thinking critically when it comes to the teachings of the cult and belief in the cult leader.   They get really good at doing it the more they do it, to the point they don't even know they ARE doing it.  That's what makes getting out of a cult so hard.