Concept number three: Moshiach shebador, bchezkas Moshiach, Moshiach vadai
Moshiach shebador means that in every generation there is an individual, (actually this individual is also the Moshe Rabbeinu of the dor) who, if the generation is worthy, will be revealed as Moshiach. Ie he has the potential to become Moshiach if that generation merits it, an if they do, he will merit the neshama of Moshiach.
Bchezkas Moshiach: this is straight up Rambam, hilchos melachim prakim 11-12 if I’m not mistaken. The Rambam defines who can be a candidate to be Moshiach, ie bchezkas Moshiach, ie if he fulfills the four criteria the Rambam states, then he is considered “Moshiach elect”
If he fulfills a further four conditions then we can be certain he is Moshiach, hence the term Moshiach vadai.
This is important to understand because a litvak will hear a lubavitcher mention Moshiach and automatically assume he means Moshiach vadai, when he could have just as easily meant Moshiach shebador or bchezkas Moshiach.