I see. So conversely, if the opposite were to occur and they were to move into a closer range where a higher level variant of the technique were to take effect, the effect would get stronger?Question 1: while nothing is set in stone (I'd likely ask the other mods their opinion) I'd say in this scenario the B-rank version of this technique would take hold. By default we need at least one hand seal for the A-ranked version and thus when we do so we activate our technique, just at a particular level. The user could use B-ranked close range if they wanted. What I'm getting at is, by removing yourself from the proximity of close range, you're still in range for the weaker. You haven't expelled the chakra from the technique you just moved into a range where the affects would be weaker. I'd personally say that in this case you'd still be under the affects of the technique if the opponent moved mid-range.
Question 2: I would say no, the technique wouldn't remain, mainly because the condition for S-rank is physical contact and not necessarily a hand seal. By removing the medium of casting, you remove the means of affect. So, while the previous scenario would be as I described it, the S-rank usage would not.
Question 3: I'll give you a hint on this one. What did we discuss about Taijin's scope? Everything regarding our existence is known to us. We can detect anything that is connected or is a part of our existence. So, the conditions in the Upper Dantian portion of this technique says that they must remove our sensory perception to break this technique. Is this possible?
Reborn weakened the hold on him to B-rank, "Tap into your upper dantian, focus internally. You know where my chakra is and you know how it's affecting you, get rid of it."
Question 4: We used the middle dantian to erase chakra within you like with genjutsu. In character I'm telling you to use your upper dantian to erase the chakra of my upper dantian. However, can you achieve the same results of erasing the chakra of another Hayabusa's upper dantian chakra within you with the middle dantian?
Question 5: I lowered my chakra down to B-rank so that you can use A-rank and above chakra. Had I maintained A-rank, you'd be incapable of conjuring chakra enough to do what I was asking you. Now, you can use A-rank and below chakra only. What level of chakra do you need at a minimum to break hold of my technique at its current level?
Q3: I get it (I think). Because we've inserted our chakra within them, so long as our chakra remains they will always be within our perception; this is achieved as a result of Taijin.
Corvo focuses on his upper dantian and pinpoints the foreign chakra that is affecting him. He could feel its effects lessen, and proceeded to expel the chakra by applying the appropriate level of strength required to lift it.
Q4: Going by the explanation you made a while back regarding the interaction between the three dantian (or lack thereof) I would say no. The three dantian all affect different planes of existence, so effects of the upper wouldn't be capable of interacting with the effects of the middle dantian (unless I'm mistaken and this concept only applies to the external component of the dantian).
Q5: S-rank. Which would leave me with the option of having to break out of range to restore my strength.