So this came up with a team that one of my players had last night:
when a flock of bats is 'attached to the base' of either 53a or b batman, it seems the flock is co-existing in the same square as the batman:

(batman 53a) Flock of Bats: Give Batman a free action to attach an adjacent friendly Flock of Bats to his base or remove an attached Flock of Bats and place it in an adjacent square; when a Flock of Bats is attached, Batman can use its special power, but do not return the flock to your starting area after using it. If Batman is KOd with a Flock of Bats attached, place any attached Flock of Bats in an adjacent square before removing him from the game.

(batman 53b) Allies In Darkness: The Caped Crusader may begin the game with a Flock of Bats attached to his base at no additional cost. While there is at least one Flock of Bats attached, The Caped Crusader can use Super Senses. You may give the attached Flock of Bats a move action to detach and move on the map. When The Caped Crusader has less than 3 Flock of Bats attached, a friendly Flock of Bats may end its move in the same square as him; if it does, attach that Flock of Bats to The Caped Crusader. If The Caped Crusader is KOd with a Flock of Bats attached, place any attached Flock of Bats in an adjacent square before removing him from the game.

and as per the PG: #099 Flock of Bats (same for all 3) If this charater takes damage, it is KO'd. While attached to another character, this character is still a character.

so I ruled (as is currently worded) that the whole 'while attached, this character is still a character' is there so it can use its powers, but also allows it to be the target of attacks, and would not block line of fire to the batman first? so the flocks can be outwitted, shot at, or you can choose to attack the flock instead of batman.

am i right?

I think they are considered off the board when they are attached to Batman, ans as such can not be attacked.

that's the thing, normally there would be wording that says that (like a vehicle pilot, capture) but the flock clarification specifically states that they are still characters when attached to the batman.

The clarification is there to say that the bats will keep actiontokens and other effects and will also push. While attached they are off the map if for nothing else it's because two characters can't occupy the same square.

If they were off the board, their powers couldn't be used, right?

Not sure how you are defining "normally" as neither Squirrel Girl, Hawkman, Penguin, Alyosha, nor Blackheart makes this specification. Vehicles are a separate mechanic altogether and are, IMHO, a bad example.

Game precedent to date is that attached figures are "off board" and not effected by on board antics. They only lend themselves to on board play if the character card specifies (as with the gaining of Super Senses) and only in that small way. I would rule that they could not be targeted, would not be KO'd by a Krakoa Earth Quake, etc.

Furthermore, ruling that they occupy the same square would, at the very least, be a violation of the Golden Rule that characters cannot occupy the same square.

i believe red king is correct.

53a can use them because his sp says he can but no you can't otherwise use their stuff.

it isn't in the pg or on the card but i'm pretty sure an orange has ruled that they are indeed off the board