What is this? A game of 12-year-olds?
Anyways...
1) Preemptive DM & Skill checks and running from room to room? and... Searching dead bodies before helping the guy bury them?
There are consequences to such things. Suppose that man burying the bodies is "greatly offended" at their behavior and tells anyone who hears it after they leave. As a result, the 15th level Ranger-Warden (or local lord) of the area confronts these "looters" and the rest of the town refuses anything to them. Can't buy anything, can't sell anything, can't get a place to stay, etc... And let's say the info spreads to many towns. Nothing lower than despicable grave-robbers.
As I recall, Detect Magic requires one to stare at something for a while to begin to figure out more than simple auras. A few rounds of staring would be odd. as would walking around "perceiving" everything. You have to walk around getting a closer look at things to perceive specific things (like secret doors and wall carvings). You just can't perceive everything from the doorway and it may take a long time. Maybe the tavern has some higher-level patrons who see right through their scheme. How many of them would like to be scoped out? Screw that! Ever consider that the NPC's make their Spellcraft check to ID a spell being cast?
2) Sorcerer taking too long.
Play out the combat in close to real time. Say, "The Orc is charging you with a battle axe and you have about 6 seconds to react." Otherwise, in RP'ing situations, the story moves forward. "That frozen, blank look you have is unnerving the other tavern patrons." Or, have an NPC's question him while he is looking up something. The NPC reacts appropriately and the PC's reputation suffers. While he's deciding what to use, the others take care of business and leave the building (leaving him behind). YOU can keep track of his spells. You know what level he is.
3) Google?
No wonder why he takes so long. I am with the others, no googling at the table. Or, just make the diseases your own variety and change it ever so slightly. Call it something new the townsfolk came up with. That'll likely piss the person off, but so be it. I'd be careful of such gamers because such perfectionists don't want to be wrong and are prone to eventual cheating and fudging rolls. (had one back in college.)