Sorry to enter late here but,
I look at Fedora as an inspiration to young Indy, the way he dressed, using hired hands (probably local, given the make up of his crew, a ute Indian, a kid, etc, not the professional student hands used on official digs). When Indy realized he wanted to be a grave robber whne he grew up he looked at Fedora as his inspiration, because he was an anit-Henry Jones. We know Indy was not thrilled with his childhood relationship with his father (insert deep quote from LC here). So when he ran into Fedora, that was as far from what Indy grew up and took him as a role model (hate to think Indy was ever so simple-minded but he was a kid).
Ravenwood on the other hand was probably someone in the middle. Not the strict by the book, Henry Jones type, but as not the rouge Fedora. I am sure Indy had a close student professor relationship with Abner and learned a lot about research and field digs, but always kept the graverobber image of Fedora with him.
Maybe Indy and Ravenwood's falling out was a bit deeper than just the broad (and yes ToJ, I am sure Ravenwood resented Indy for laying the pipe). I wonder if the falling out was a bit of guilt Indy had on his "own methods" of field research, which were not like Ravenwood, and he did not want Abner to see that Indy had become nothing more than a grave robber with a Profeesor gig. I feel Indy let Marion be an excuse to tear away from Abner and his father, only Marcus was willing to turn the other way and provide Indy with pay. We know from LC that Marcus was not really good at anything, heck he even got laost in his own Museum. So Marcus i am sure was just happy to have a steady flow of "good objects" coming in and would not ask questions that Henry or Abner would have asked. I wonder if Indy was ashamed of his methods and motives, and let himself be a loner and lose contact witht he people close to him. I don not think Abner was a rough and tumble type like Indy, but if they want to make Indy IV the quest for Ravenwood, then the back story might be better if he was.