Needless to say, a few Orthodox demur. Perry Robinson, e.g., asks a series of questions that would require a treatise to answer fully. I answer here, in brief, the ones clear enough to admit a clear answer.
1. What is the authoritative teaching regarding Original Justice? The same with Original Holiness. How are they acquired?
Such questions are pertinent because original sin must be understood in contrast with what the CCC terms "original justice and holiness" ('OJH' for short; in this context, the terms 'justice' and 'holiness' have a different sense but the same reference.) OJH is simply that unmerited state of unity with God which was bestowed on our first parents (and on Mary) by divine grace. It is incipient beatitude, but not developed because there is as yet no exercise of moral virtue to develop it.
2. What would the mere lack of original justice or holiness imply in the Catholic evaluation?
The catechism passages quoted by Fr. Kimel make clear that original sin is the "deprivation" of OJH; accordingly, there is no "mere lack" of OJH. Original sin is the lack of something that God meant for humanity to have, namely a state of graced unity with him. Hence, by losing OJH through their choice, our first parents caused corruption in their own nature, which is also our nature; hence we inherit not merely the absence of OJH, which is original sin, but also the effects of its voluntary loss through the first sin. We are deprived, not merely lacking.
3. What is the “sin” that was transmitted? Is it something natural or personal? If the former, why didn’t Jesus have it since he is consubstantial with humanity? If personal how is this possible?
As already indicated, the "sin" in question is really a state of deprivation; that in turn has certain effects, such as death, weakness of will, and darkness of intellect.
Inherited, original sin is not personal, if by 'personal' is meant 'brought about by the personal activity of the one inheriting it'. But it is personal in the sense that we can and do become complicit in it by our choices. Although original sin does not of itself make any particular, actual sin inevitable, inheriting it does make inevitable that anybody who is able to exercise moral responsibility will each commit some-or-other actual sin at some time. And when we actually sin, we become personally complicit in original sin understood as deprivation of OJH; it is as if we joined Adam and Eve in their first sin.
Similarly, original sin is not "natural" in the way our having bodies is natural. Without at least having come to be as a bodily creature, you can't be a human being; but all sides take for granted that at least two humans, our first parents, began their existence without sin of any kind. Yet original sin is "natural" in that, once they freely committed the first (human) sin, human nature was partially corrupted for themselves and all their descendants willy-nilly.