In the 1st picture on the left is your unknotted eight as i read it,
Your eight, that is not an eight but stays unknotted is much more slick.
And you have read it very well, that's the one i was refering to, (i usually am no good at providing worded tying instructions).

However, i do not make out any vulnerability at this three rope diameter instance, that might initiate tail slippage, or some other security hole at cyclic loading or slack shaking loading impulses.
Note that Scott's locked bowline, also uses an unknotted collar component, but as far as i know, it has been characterised as inherently secure.
There is another knot that seems as sturdy and TIB, looks like an eight but isn't, tail seems to go into the nipping loop a third time, but doesn't.
on the right the other that is actually off the scott's lock variation topic when looked closely.
With respect to your first image, rightmost, TIB variation, it looks legitimate too, it also uses three rope diameter inside the nipping loop(?), of an overhand based collar stabilizer, which, IMO, is not alleged to introduce any tail slickness.
The tail wrapping around the outgoing leg is a weakness or as an advantage for security?
How does it compare to the similar knot shown in the second pic?
It looks like you are advancing two schools of thought here, with respect to bowline development

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1) I do not see the tail wrapping around the out-going eye leg as a weakness (first image approach), because if i did, i would had devalued many of the inherently secure bowlines, that are used in the field, without reported failures so far.
In fact, i myself, have used this technique, at many of my very own creations.
2) Yet still, i think i am going to lean towards your second image approach,
which exploits the so called Janus mechanism.In my view, the second collar formation around the on going eye leg, expands the bowline collar function, providing me two bights with their legs nipped that i can handle after heavy loading, along with the apropriate nip constriction, in order to reach the security standards.
Very good, i sense you're going to feed this forum with a whole lot of fresh TIB bowlines

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