Legal settlements typically exclude any further legal action regarding the complaints contained in the original lawsuit. Don't count on any cost recovery.
Again, check your facts. ALPA's case against UAL is not "further action regarding the complaints contained in the original lawsuit." ALPA's suit is in relation to the agreement UAL signed indemnifying ALPA against any legal liability resulting from distributing the pension termination funds.
Furthermore, insurance companies footing part of the bill doesn't make me feel any better.
It should. It's proof that ALPA has been very smart in how they manage risk and protect their members' money. Any other pilots' union would have been bankrupted. Thanks to smart planning by smart attorneys and accountants, the union is still in fine shape and pilots are not at any risk of losing union representation or their money.