May I become a 50/50 partner with a non -frum jew who wants to keep the business ( dental practice) open on yom tov, possibly Shabbos?
If I can’t get the benefit of the work and pay non-Jewish employees, can I stipulate that if he were to run the business on Shabbos/yom tov, he would have to pay the staff and get all the revenue from work on Shabbos/Y’T? Would that constitute lifnei iver?
Yes it would because you are causing him to have more sechar shabbos. There is also another issue here, that your business is open on shabbos, which is maris ayin, and even if your partner would be a gentile it would not be permitted.