I think the truth is somewhere in the middle for all three.
Lili is the only one who I think likely would have started, as we were in need of a seasoned combo guard the season she sat out. (She left for ahem other reasons, sitting out rather than playing her senior season.)
Marta is more complicated - she sat out due to thumb surgery and then we didn't have a scholly for her to come back, so I think she realized the writing on the wall mid-season and sat out to preserve her eligibility. I genuinely think Tara would have wanted her back if there had been a spot, as Tara loves future coaches and sang Marta's praises disproportionate (IMHO) to her on court contributions. Whether she would have started but then sat a lot, or come off the bench, who knows. But she would have been a core part of the team.
But I do think Dodson's situation would have looked more like Jerome's, because we just have so many offensively talented bigs and two, Brink and Prechtel, are solid outside shooters, much like Jerome has been in the past, and which Dodson decidedly is not. She is a 5 through and through and we just have too many multi-talented bigs to need a have who isn't a blocking and rebounding machine.
On a more personal note, Stanford is a very "small school" undergraduate environment and I think those who stick around for a co-term or fifth year often feel a bit dislodged once their class graduates. There are very very few transfers in and out and few who graduate in more than 4 years, so I can see the temptation to try something new (and pick up a free grad degree) rather than feel like a hanger on.