In the following post
… under #3 we have:
“…the manomaya kāya (gandhabba) may live for thousands of years in the human bhava”
I’m assuming that a gandhabba can stay in the gandhabba form for thousands of year straight, without birth (jati) as a human with a physical body.
I found the following thing you said interesting:
“One ghost they saw was of a girl who was near her own portrait in a palace/museum they visited.”
Is this an example of attachment (tanha)? i.e. attachment to the previous physical human existence?