Since it is more than you two being married, I would have made sure that everyone would get to meet and spend time with everyone before moving together, but it seems that you have already made it to the visa phase, while skipping that part. It seems backward to move half of the family, if it is not going to be possible to live all together; as @Ontarkie stated, whatever adjustments are required will need more than 90 days anyway. You and your partner probably know your kids best, so work out a plan together? Is your home large enough for everyone, if so, might has well prepare the nest for the new blended family, no?
Best of luck to you and your family.