1)when you have a situation where you have 3 poskim to choose from- can I choose the rav that will give me the psak I want to get i.e. maykal ?
I certainly don’t think that’s what the RS”O wants us to do.
2)if I cannot get a rav now (Im on vacation, or it’s midnight, or the rav doesn’t answer his phone etc) can i rely on a heter in a situation where i know it is a machlokes?
I’m going to evade your question now – get a hold of the number for an emergency halacha hotline.
When that’s not possible, I would think that it depends on the circumstance; if nobody would be effected negatively by being machmir, I would think that would be the way to go, and then ask when you get a chance so you’ll know for the future. Otherwise, it’s a real tough call and not really an answerable question.