1. The only “rupas” (at or above the hadaya vatthu/suddhatthaka stage) in mano loka are the hadaya vatthus of the arupavacara Brahmas.
– A hadaya vatthu is right at the suddhāṭṭhaka stage.
– It cannot be seen by anyone but a Buddha.
2. Ancient yogis were able to “see” rupavacara Brahmas. But they could not see arupavacara Brahmas.
– That is why the term “arupavacara” came to use.
– Of course, there are no other rupas at or above the suddhāṭṭhaka stage in the arupavacara realms.
3. Hadaya vatthu of arupavacara Brahmas do not belong to viññāṇa dhātu.
– Only dhammā below the suddhāṭṭhaka AND namagotta (memory records) belong to viññāṇa dhātu.