The fact that the -ness endings are hyphenated in this sentence indicates that the writer has made up these words by adding -ness to an existing word.
Generally we add the suffix ness to convert an adjective that describes a quality to a noun that describes the corresponding quality, when there isn't already an appropriate noun available. For example, good (adj) + ness give goodness (noun).
If the writer had added -ness to an adjective, we would know exactly what the made up word was supposed to mean. In this case, the writer has added them to pronouns and verbs, so the standard interpretation would not apply.
My guess is that, given that this is about spirituality, it is a rather crude attempt to talk about a move away from thinking of things in terms of how it relates to oneself (I-ness) to thinking about things as having an existence in their own right (be-ness, is-ness).