Will the x4s work on the osmo?

No. It's because it processes images different than the previous X3 or X5 where it's done in the Inspire 2, so it's incompatible with the Osmo handle. DJI has said they'll be making a handle for the X4s/X5s, but that's all the details both we and the company knows. We have no clue on timing, stage of development, or anything.