Inspire Greatness

And Armin Brenner Jann Berger does not pay for them...

Non-existant user wrote:

And Armin Brenner does not pay for them...

Well, Armin pay it. You're thinking of Jan Berger.

It could be fun to see a Nocturn with 7 strength ;p

(I think it's better with Ossian + Rave)

Would work great with Muddles too especially if you play with Leech+Immortal Grapple.

Would there be a window for using inspire greatness on a blood brother ambush, after they're put in play but before they enter combat?

Blood Brother Ambush
Type: Action Modifier
Requires: Brujah antitribu
Cost: 2 blood
Only usable when an action is blocked.
Combat does not occur. Put this card into play. While in play, this card represents an ally with 3 life and 2 strength who can strike for 2R damage; this ally enters combat with the blocking minion. Blood Brothers may play cards requiring basic Potence as a vampire with a capacity of 3. Any cost in blood is paid with life. If a card would give them blood, give them life instead. Burn this card at the end of combat or if the combat is canceled

Edit: Thanks Reyda, forgot the acting part!

No, because the Blood Brothers Ambush are absolutely not an "acting minion" (card text on inspire greatness)