Hey there.  I'm filming a track and field event and my production assistant bailed on me.  I would like to know if I am able to connect to both the Phantom 4 and Osmo+ at the same time on the same iphone?  Thanks!

Technically, it is impossible if you use all the DJI devices using WIFI connection because WIFI connection only allow you to connect one AP at a time.
But also technically, using DJI GO under connection of WIFI with your OSMO and use GO 4 under connection with your remote controller, that probably can let you connect with your two devices.

Anyhow, I think using two different smart devices would be the pretty much better way because using two DJI devices at one device means more battery consumption and always requires switching apps.