iApps with load ucs Platform-migrate on newer hardware

I see that iApps are deprecated and the latest recommendation is using FAST

1. When we load UCS file from iSeries to RSeries using platform migrate. How are iApps copied? or Are they not copied and we are supposed to do it manually by using either enabling deprecated iApps or FAST?

2. Is it a good practice to load the config after the new pair of F5s are in HA with no VIPs but just self IPs and VLANS