My arguments for yes:
RAW: They both say that its while you're in the square. There's no mention of how you get in there being connected to the bonuses. In the mousers case its an entirely separate paragraph.
Sense: I think the case for the stunning fist/penache expenditure being the cause is more than a little weak (especially for the mouser) On round 4, why would it matter if the mouser/Monkey shiner entered the square through the stunning fist or penache expenditure on round 1 or if they just walked into the square?
Power: A mouser gives up parry riposte: a swashbucklers strongest ability, for some nice, tactical and thematic but not overwhelming bonuses.
Monkey shine is an ELEVENTH LEVEL feat with SEVEN prerequisites. It should be roflstomp good. (yes, the style master can snag it early... thats a huge problem with the style master)
I've been playing my Fox Shaped kitsune since shortly after they were allowed in PFS, and I have yet to encounter a GM who has vetoed my use of these abilities after entering a creature's square by alternate means.
But I accept that a GM could rule in such a way, since there is a bit of uncertainty.
In any case, once you reach high level play, the mid level advantages of this type of character start to drop off and GMs normally have bigger fish to fry when it comes to balance. (and since you're also fairly weak during the first few levels, you only really feel OP for a short time... so enjoy it :)
I agree with what everyone has said. I also play a Fox Shaped Kitsune in PFS and my experiences match Byakko's.
In fact, the closest I have come to someone even questioning the rule is asking to read it and that recently happened at Gencon. They agreed that my (our) reading is correct and the game quickly moved on.