I can't tell you what I think all the fetters refer to, but, for practical purposes, I can tell you minimum standards for some of them that I think their elimination entails that one will meet:
At minimum: understanding and agreeing with the 4NTs.
Not everyone who severs this may know what the 4NTs are, or have thought about them, so naturally this criterion isn't "agrees
with the 4NTs" but "would agree with them dependent on knowledge concerning them".
A key issue here is that the meaning of "craving" be understood in line with what the suttas are explicitly saying (e.g. craving for sensuality is part of the root of suffering, craving for sensuality can end, craving for sensuality is the everyday wanting of sex, food, social status, money, power, desire-fulfillment, etc. in gross and subtle forms.)
I would say that, without knowledge concerning the 4NTs, a person in whom this fetter is severed, who is of normal intelligence, would be able to explain, in a simple way, using terminology that may be idiosyncratic, that craving is the cause of suffering, craving can be reduced via some kind of practice however conceived, and craving includes the everyday wanting of sex, food, social status, money, power, desire-fulfillment, etc. in gross and subtle forms, however those things are understood to manifest in experience.
Desire for sensuality. Any experience, body sensation, etc. that has any unpleasant quality (no matter how refined) apart from pure vedana which non-coincidentally relates to the urge or motivation to attain some sensual thing.
Any experience, body sensation, etc. that has any unpleasant quality (no matter how refined) apart from pure vedana which non-coincidentally relates to dislike, annoyance, rejection, anger, etc. Not necessarily aimed at another person (could be dislike for events, dislike for oneself, dislike for an experience, etc.)
What is "pure vedana"? Meditative analysis allows one to distinguish between a pure unpleasant sensation, and vibratory unpleasant stuff that is directly tied into cognition / emotion / motivation. The latter can be seen to be happening separately from the former. The existence of the latter is indicative of the continued existence of some fetter in my view. The existence of the former appears to be a consequence of human existence.
That seems like a good start for now.
a) reality testing based on stream enters we know (and we could even question what is meant by "stream entry", realizing that beyond a certain point if there is insufficient consensus on basic concepts then this will be less productive)
The problem of lack of consensus regarding this is larger than you may think, in my opinion.
Bhante V, for example, has an explicit criterion for "fruition of stream entry" (which permanent affects the relevant fetters) which is not the Burmese Theravada criterion. (As he practiced in the Burmese tradition and claims to have attained various things in that tradition before rejecting it, it is probably fair to say that he explicitly rejects fruition-as-you-understand-it as related to "fruition of stream entry".)
I personally don't know if I buy his theory (that fruition for each path involves seeing the operation of dependent origination in a special way), but I had an experience of seeing (some aspects of) dependent origination which was profoundly transformative, so I am not keen to write off what he says (though I do not claim that it meets or doesn't meet his criterion for what "seeing dependent origination" involves, as I am not familiar with his complete theory about dependent origination).
d) keeping this finally about how adopting a view improves or detracts from practice, realizing that all the factors that make for optimal practice, whatever that is, can't easily be known
The most obvious way this ties into practice, in my view, is that it provides high standards for what various attainments mean, which will help a person actually attain those things if those things are possible to attain through practice and if they are inclined to attain those things.