I'd rank them
Lawrence is a pretty good pitcher, and should have a solid ERA and WHIP. The problem is his team is dreadful, and he won't get many wins. If you can take the WHIP hit, I'd hold on to Ischii, because he does get a decent amount of K's and is on a good team, that should win games. He could win 15 games easily. I expect his ERA to go up eventually, to around the 4.00 to 4.50 area, still not horrible. Foppert is too young and unproven to be messing around with in mixed leagues.