I am looking for a guide that gives me information about how to commmunicate with familiars, summons and bounded creatures. E.g. can I summon an elementa and ask him where to find a specific item in his plane or even if he could get that for me? Can I summon the same creature again so he can give me this item? Or can I summon an evil outsider to play cards with me. What will happen when they encounter my paladin?
If I have an eagle, can he tell me what he saw? If I try to bind an angel and we like each other is it possible that he accompanies me for the next month?
To quote James Jacobs:
On Golarion, if you use a calling spell to conjure an outsider, and then kill it, it dies as surely as if you killed it on its home plane. If you instead use a summon spell to conjure an outsider, the thing you summon isn't real before and after the summon spell ends. It doesn't "go back" to an outer plane when you kill it or dismiss it or the spell ends... it just stops existing, just as it didn't exist before you cast the spell in the first place.
Sure, that's fluff and not rules. But you shouldn't be able to use a low-level spell as Summon Monster to gain information about other planes and such things. So no asking a summoned elemental about the whereabouts of specific items. And you can certainly not use summon monster for a servant who retrieves items from other planes for you. Don't make summon monsters and casters better than they already are.
If you want a "real" outsider who does your bidding, travels to other planes by itself and knows stuff you'd use planar ally and a similar spell.
As for attacking your party paladin, summon monster handles this:
It appears where you designate and acts immediately, on your turn. It attacks your opponents to the best of its ability. If you can communicate with the creature, you can direct it not to attack, to attack particular enemies, or to perform other actions.
So unless you consider the paladin an opponent, your summoned creature won't attack her.
Familiars are handled here. They are true 'individuals' unlike summoned creatures. They are an extension of your player character, yet in some respects they're more like allies - NPCs - and thus within the domain of the gamemaster. So who's in control of a familiar isn't always clear cut. More on this way down in the article.
As you can see on that page, familiars gain 'Speak with master' when the master reaches level 5. By then, by all means, your owl can fly ahead you and return to tell you what it saw. However, even before that a familiar has an Intelligence score of 6 or 7. That's well within human intelligence (albeit in the low range). While the familiar doesn't have a language, it can still grasp pretty complex concepts - it's much smarter than a common animal. Compare it with communicating with a person with which you share no common language.