Yuuka actually has 115m HP, but once you bring her HP to 102.5m, she focuses and her HP resets to 2.5m (no matter what it was before), and then she will only use a Focus -> Master Spark -> Focus -> Master Spark -. Repeat pattern. With 32 PAR resistance, it means she's basically guaranteed to get that Focus off, but it will always reset her HP to 2.5m.
As for Eiki, she just has 14m HP, and she will use Last Judgment every 5 turns. Also, when her HP is below 50% (that is, 7m), and it has been 3 or less turns since she last used Last Judgment, she has a 20% chance to use Focus and Game Over you on the next turn (this is mainly so Bar of Ten Kings doesn't interrupt her normal Last Judgment attack - not sure why), so basically unlike Yuuka, she can use it any time she wants once her HP goes below half. It's pretty much entirely up to chance whether she fires it with 6.5m HP left or she doesn't fire it off at all.