Fiance visa with mobility case implication?

[Girl777 2]

Hi everyone

I have the following situation. I am canadian and my fiancé is us citizen. I want to move to us to make a family with him there. I have a son of five y.o. and sole custody but when his father opposes the move , I will have to go to court with mobility case to get permission for my son. Time of this process impossible to estimate as courts are slow. The othere nuance is that it is good to go to court with some proof of commitment like start of fiance visa application or marriage. Since my fiance only agrees to fiance visa now, I would like to know if it is possible to give it a stsrt and then go through court process for my son so noone will be pressing with any deadlines and then do final steps of fiance visa application and waiting time and k 2 for my son. We thought once we get package to fill in,I will go to court and will fill it in only after I am done with mobility issue but my fiance told me he found out tofay that they said at the embassy once you start application then at some point interview will come up and I will have a deadline for everything and with court implications this does not fit me.

Also other question, my fiance thinks marriage and green card will take took long. Is is true? What are waiting times for that process and can I travel to usa while waiting?

Thanks everyone