So I'm wondering, if you are invisible and a creature has See Invisibility, can you still attempt to stealth against them? See Invisibility makes invisible creatures and objects "appear as translucent shapes", and they are still treated as Concealed. Since you are still Concealed even when they have See Invisibility, can you make Hide checks to become Sensed and Stealth checks to become Unseen? Theoretically this makes sense, the translucent shapes thing makes it sound like they can't see you well, so you could theoretically use your stealth skills to slip out of proper visibility, just as if you were standing in dim light being observed by someone who doesn't have low light or darkvision.
As far as I know this is allowed, and it makes sense, and as far as I know there is no indicator in the spell or elsewhere that the concealment occurring as a result of this spell is any different than regular concealment. But despite that there is still the nagging thought that this is like PF1 Blur and Displacement kind of thing where someone has concealment/total concealment but can't use it to stealth.
Yes, you can use stealth while invisible and that could potentially beat See Invisibility. However you'd still need to succeed on the stealth check(s) and you couldn't take any action that isn't allowed by the stealth skill (which is pretty much any action).
But despite that there is still the nagging thought that this is like PF1 Blur and Displacement kind of thing where someone has concealment/total concealment but can't use it to stealth.
That's an extremely bad example. To my knowledge Paizo has never clarified what happened there, and a lot of people (myself included) believe the Ultimate Intrigue rules text in question is an oversight in the same vein as "Prone Shooter" and should just be ignored as a result. The rules in the core rulebook are very clear that any concealment will do for satisfying the requirements of stealth, and there is no exception for blur. A single sentence in a campaign advice section of another book is not anywhere near sufficient to override the clear rules in the CRB. Of course, that one sentence has caused mountains of forum debates for something that almost never comes up (invisibility is a 2nd level spell, it's going to be a rare day that someone casts blur in order to use stealth).
While on the general topic, under using Perception to find invisible targets I recall the rules saying,"If you beat the invisible creature's stealth roll then you know what square it's in or get a clue." Do we have anything more concrete that that? Seems like pinpointing an invisible creature just by succeeding a single Perception check is too easy and only getting a "clue" is too vague. Is there any clarification of this, or did I read something wrong, or is it really that vague?
I mean, knowing what square it's in is pretty clear. I figured the detail is purposefully left to the GM. Maybe you pick up a disturbance in the air, an odd behavior of light, catch the sound of a boot scuffing from that area, etc. I don't have any problems with mechanics being stated clearly with flavor left to the GM. At least not usually.
Blur being 2nd level and Invisibility being fricking amazing is a good argument for Invisibility moving to 3rd or 4th level, and the improved version going higher still.
Honestly, with its new 1 minute duration and how tight spells per day are, I feel it should be dropped down to 1st level.