Most challenging trip

This Europe trip is definitely my most challenging trip that i planned so far. Within the span of my 30 days in Europe from 31 May to 29 Jun, there are...

1 pax joining on 1 Jun, 1 pax leaving on 6 Jun, 3 pax joining on 8 Jun morning, 1 pax joining on 8 Jun night, 1 pax leaving on 18 Jun, 1 possible pax joining on 21 Jun, 1 possible pax leaving on 28 Jun.

Now this is what i call a trip planning challenge. Luckily they got some experienced hands here.