I wonder if your W's dad resented the idea of giving anything to his first wife's daughters because it felt like giving something to his first wife, or helping her in some way. If he remained bitter about being cheated on it's possible he transferred that onto his daughters. It must have been horrible for your W to be cast aside like that for her dad's new family.
I think it was really driven by the fact that he had a new family he lived with 24x7 that were always front and center, and I'm sure his second wife wasn't going out of her way to make sure he was spending money on his daughters from his first marriage. I don't think it was a transfer of bitterness more just shifted priority and out of sight out of mind. It was horrible for W and even worse for her younger sister who is still in therapy over it. W had a nervous breakdown at the time. The impact was so profound that I was absolutely convinced that she would value marriage and intact family and therefore would not cheat or seek to divorce me without serious problems on my part. I was wrong about that and ironically so no parallel to the fact that her mother had cheated and asked for divorce.
WRT the lawyer, I was thinking lawyer first because they will take the most extreme position in your favor or at least advise you on the possible range for each parameter. They are also most likely to make the most significant changes to structure and meaning. I would want to see where that leads first so that you don't spend time with the financial planner and negotiating with H only to do it all over again if something is seriously amiss. I would stake out the opposite pole then negotiate toward the center rather than trying to inch H away from his position. That's how they do it on "Pawn Stars" -- immediately offer half of what the other person wants and then move away from that slowly.
You don't have to antagonize him if you have a dramatically different ask, you can do it respectfully. "I've seen your proposal, here is what I would like to see, let's try to meet somewhere in the middle." I would of course try to be fair but I also wouldn't want to give an inch more than I had to.
Accuray
Married 18, Together 20, Now Divorced M: 48, W: 50, D: 18, S: 16, D: 12 Bomb Dropped (EA, D): 7/13/11 Start Reconcile: 8/15/11 Bomb Dropped (EA, D): 5/1/2014 (Divorced) In a New Relationship: 3/2015