Fate 3.0 Rules Questions (not setting, mechanical questions on the system)

[The Codex]

Ok want to expand this example a little, as have an email conversation to one of my potential players and he has a fair and interesting question of what happens next from the example.

So his character reaches the little girl and the thug has been able to get her.

He then wants to do the following shoot the steam pipe next to the thug to tag the manuever blinded. all seems fair so far. he then tags it for free to dodge the stumbling thug with little girl in his arms (-1 as might is lower than athletics), in the next turn can he tag blinded a second time (would not work if only a fragile aspect right?) to allow him to do a stealth/athletics role to slip into the shadows to escape the thug?

[Ophidimancer]

If the one guy blocks the baddie from attacking the girl through a cover fire or something, then he can't attack the girl, can he?

He can if he scores high enough to bypass the Block.  Basically the Blocking character is trying to replace the girl's Defense by directly raising the difficulty to hit her.  She might get hit anyway, but the shifts of stress she takes will be determined by the attacker's successes minus the Block successes or the girl's Defense whichever is higher!

So say the attacker gets 6 successes, the Blocker got 5 successes and the girl got 4 on her Defense roll.  The girl only takes 1 stress, not 2.

[Ophidimancer]

He then wants to do the following shoot the steam pipe next to the thug to tag the manuever blinded. all seems fair so far. he then tags it for free to dodge the stumbling thug with little girl in his arms (-1 as might is lower than athletics), in the next turn can he tag blinded a second time (would not work if only a fragile aspect right?) to allow him to do a stealth/athletics role to slip into the shadows to escape the thug?

The second one wouldn't be a tag, since it wouldn't be free, it would be an invoke, compel, or declaration and would cost a FP.

[Papa Gruff]

The second one wouldn't be a tag, since it wouldn't be free, it would be an invoke, compel, or declaration and would cost a FP.

Quite right. The good guy doesn't need to tag the aspect for defense though. If he decides that he can dodge the bad guy easy enough without tagging, then he still can tag the aspect on his next attack action for free. The fragile aspect holes the hole of the next exchange.