So, I motivated myself enough to finally enact the "Unholy Rite of the Console" and tested my questions to some degree of understanding. May the following enlighten you. That is, unless you already knew and I was the only one in the dark... which would make me sad.
Counters for a SelfBuff seem to disappear when the SelfBuff times out, though if you spam the SelfBuffs enough, some of the Counters do seem to stay up after the SelfBuff times out, while a few more might drop off within the next few minutes. However, while these lagging Counters remain, one DOES receive the benefits of Precision for those Counters that remain after the SelfBuffs have timed out.
Inner Focus will only add Counters for a SelfBuff IF you use the same SelfBuff's proc to trigger it. e.g, Thousand Cuts will yield Thousand Cuts Counters, but not Sweeping Strike or BladeDancing, and the same is true for the other two. I tested this by running around with only one of the three SelfBuffs active. With an 18% chance you'd think I'd get a Thousand Cuts Counter after slaughtering most anything that moved in the first two areas on the way to the Wellspring. Such was not the case. I tested each of the 3 SelfBuffs in Combat separately.
It would be logical to conclude that one cannot generate Counters for a skill which one cannot proc, such as in the case of of those lagging Counters from spamming the SelfBuffs. The SelfBuff itself reads that it enables the proc, but the Counters are only how many times it might proc. I unfortunately only had this thought after I deleted the character and started on this post, so I did not test if by some chance having a Counter but no SelfBuff would trigger an Inner Focus proc.
As a side note, the proc rate for individual SelfBuffs listed under Inner Focus were dreadfully low in actual use. The rate of gathering Thunder Counters from ThunderStorm was far more satisfactory, even though it required a kill. If the proc rate for Inner Focus was much higher, it might actually pose as a viable investment, but for the 20 seconds you have for the SelfBuff active with the 5 (or
Counters available, you're not likely to see more than 1 additional Counter for Thousand Cuts every other time you refresh your Counters manually through activating the SelfBuff. Mind you, all of these numbers were tested at Rank 15 of each skill, at Character Level 100, so imagine how much worse it would be leveling up!
tl;dr Inner Focus is a waste of points. Spam SelfBuffs instead.