In Theravada, there are five khandha (aggregates), namely, materiality, feeling, perception, mental formation (sankhara) & consciousness (vinnana).
Alaya Vinnana and Manas Vinnana is not supported in Theravada because alaya & manas are sankhara khandha rather than vinnana khandha.
Alaya is 'citta', which is 'sankhara khandha' & not vinnana khandha.
Manas is thinking & intellect, which is 'sankhara khandha' & not vinnana khandha.
Vinnana is the basic awareness that knows sights, sounds, smells, tastes, touches & mental objects, where these mental objects include citta & manas.
Since citta (alaya) and manas are objects of consciousness & are sankhara khandha, they are not a type of consciousness because they are objects (ayatana), similar to how a sound or smell is not consciousness but an object (ayatana).
The above should explain why these ideas of Alaya Vinnana and Manas Vinnana are not supported by Theravada.
An analogy is required here to prevent misunderstanding.
Imagine there is a bathroom with six mirrors, electric power points (wall sockets) & a bathroom cabinet to store soap, shampoo, razors, etc.
In this bathroom:
The six mirrors are the six consciousnesses, which have a purpose of merely reflecting;
The electric power points are 'manas', which have the purpose of thinking, decision making, intention, etc; and
The bathroom cabinet is 'alaya' or 'citta', which stores emotions, defilements, tendencies, wisdom, metta, etc.
Its like a computer, with six computer screens.
In this computer:
The six computer screens are like the six consciousness.
The CPU is like manas.
The hard drive is like alaya or citta.
Manas & alaya are not types of consciouness. These two ideas, namely, manas vinanna & alaya vinnana, arise from a miscomprehension of mental reality. Its like believing a dog is a planet.