Q77: Could someone use the Cool Head, Freerunner, Sure Hand and Sweet Talker feats and then later retrain the feat, but keep the knowledge of the skill trick?
Could a Chameleon use his floating feat to learn as many skill tricks as they can, at no skill point cost?
The feats says that the characters learn the tricks, not that it gives them access to them. It's not game breaking, but 20 skill points on a skill starved build could help.
A77: Not likely. Even if it worked by RAW (which I don't think it does, although it's not exactly clear-cut), you can expect most DMs to shoot it down.
Q79
Which feat allows a Cleric to use Int in place of Wis for spellcasting Stat and what is it's source?
A79: AFAIK no such feat exists. I know there's a Monk feat that changes Monk abilities to work off Int (2, actually) and a Paladin feat that changes Paladin abilities to work off Wis. There's also the Archivist, which is split Int/Wis casting and primarily casts from the Cleric list, although that's a distinct class, not a feat.
q80. whats the trick with knowledge devotion to gain a insight bonus to atk/dmg. can someone break it down for me how it works?
A80: At any point you spend a free action to make a knowledge check regarding the monster. You get one check per monster per combat. There's a table next to the feat description that tells you what bonus you get for your check result.
Q 81 I want to advance an NPC. It's a ranger/sorcerer. Is there a feat that'll blend them together well, and what PrCs complement this pairing?
A81: There really isn't a PrC that works exceptionally well with this pairing. You can either use the usual Gish PrCs if you want to advance combat and spellcasting, or Unseen Seer if you want to advance the nature-ish skillmonkey angle. You might want to tweak Unseen Seer to give more Favored Enemy bonuses instead of Skirmish/Sneak Attack bonuses.
As far as feats go, again there's nothing that explicitly pairs Ranger and Sorcerer. There might be a 3.0 feat around somewhere that adds your FE bonus to spell DCs, but that's really not explicitly Ranger/Sorcerer and I can't remember where it would be right now.