Any living being is born with an “ekaja kaya” and it has hadaya vatthu.
An asanna being also has an ekaja kaya, but it is fully shielded by its physical boy. That “body” does not have the ability to interact with the external world at all.
– It is very similar to an arupavacara Brahma, except that an arupavacara Brahma’s hadaya vatthu is not shielded and it can directly interact with “dhammā” and generate thoughts.
There is a difference between bhavanga and bhavanga citta. See, “Bhava and Bhavanga – Simply Explained!”
Since you can understand Sinhala, you may want to listen to the following discourse by Wahraka Thero:
“ධර්ම දේශනා 1”
In particular, listen to the segment starting at 1:16:00 hours. But it is best to listen to the whole discourse.
I see your reference in Bhikkhu Bodhi’s book. As I said before, there are several contradictions in that book, even though mostly correct.
P.S.
The difference between plants and living beings is that plants only have jivitindriya and no hadaya vatthu. Thus its life is sustained by kammic energy, but it cannot generate citta.
– But even in an asanna-being bhavanga is active the whole time. The “bhavanga state” has nothing to do with citta (thoughts). Therefore, an asanna-being is not aware of anything.