To expand upon this answer, below is the definition of a familiar and spawnpoint from the Complete Codex:
Familiar (Object Trait)
This object can cast spells. See "Familiars" on page 16MWC.
Spawnpoint (Object Trait)
This object can cast spells during the Deployment Phase. See "Spawnpoints" on page 16MWC.
If you look on page 16 it goes into further details as to the mechanics, but this definition tells us everything that is important to answer the question regarding revealing enchantments. Familiars and Spawnpoints are objects that are able to
cast spells. There is nothing anywhere in the rules that allows familiars to do more than cast a spell unless the card specifically states so. Even channeling mana is not an innate property of these objects unless it's printed on the card. The only thing that Familiars and Spawnpoints can inherently do is cast spells.
Now for the really important thing to remember. Revealing an Enchantment is not the same thing as casting a spell. Casting a spell, to summarize in my own words, is simply putting it into play. To put it in the words of the rule book, casting a spell starts with Declaring the Spell and ends with Resolving the Spell. For an enchantment, the spell is resolved when you put it face down. Later revealing it doesn't have to go through any of the steps for spell casting and is a separate beast entirely.
Thus, since Familiars and Spawnpoints are only able to cast spells, and since revealing an enchantment is not the same thing as casting a spell, Familiars and Spawnpoints can not be used to reveal an enchantment.
Now, as far as tapping into the mana supply of a non-mage object, the short and sweet of it is that you can only do this whenever you are explicitly told that you can. Familiars and Spawnpoints have a general rule that allows you to do this when using them to cast a spell. There are also some cards like [mwcard=MWSTX2FFJ05]
Construction Yard[/mwcard] that give you access to mana, even without being a Familiar or Spawnpoint. Any time not explicitly permitted is off limits.