Nibal,
The very short and most simple answer to your questions is that it is totally up to you on how you want to irrigate. As the designer, you are going to need to have a vision about what the overall goal is with how the water is to be applied, what the plant will need as it grows, and how you intend on maintaining that irrigation system so it can adapt/grow with the plants as they mature.
Typically, trees should either be on their own valve, or have enough emitters to each tree to match the precip of the rest of the shrub zone. Understanding that shrubs will need a different amount and frequency of water than trees due to root zone, species, etc. So understanding this, I would not put the shrubs solely on the tree zone since you will need to be more frequent with watering shrubs over a longer span of time.
Trees in turf is always a risky move because you are literally combining the highest water need plant (turf) with a very low water use plant (tree), depending on the species of course. Again, going back to proper design and vision for what you are going for, the trees should not be placed in turf without a generous size tree ring surrounding it. Typically the tree ring should be the size of the tree canopy. This will not only help protect the tree from machine damage, but allow the tree proper irrigation and prevent soil compaction from foot traffic.
As the tree matures, you should be able to phase out the tree irrigation and allow the tree to live off of the turf irrigation water (since the roots of the tree will be spread throughout the turf area, using the turfs water as its own). Again, totally up to you.
I hope this helps answer your questions, and please note that this is just scratching the surface of things to consider and is not the only way to think about how you design or irrigate these types of situations.