I have this tall variegated pittosporum along our back fence that is struggling for sunlight due to the Crabapple on one side and a large Photina on the other (north side). Our plan is to cut back the Photina's at some point, but in the interim, I was going to air layer the Pittosporum because I love the leaves on this tree,I find myself looking at everything with bonsai eyes.

I've been circling this tree for weeks now and I thought the whole tree itself would be a great Bonsai prospect as the base is large, but not too big. So I've added a few photos from today and my questions are:
1. Is it too late in the season to attempt air layering, there are lot of branches that could be candidates?
2. How many air layers at one time is too many, I was thinking maybe four?
3. Should I feed the tree during the air layer period? This tree has just been left to its own devices for 16 yrs.
3. Based on the following photos, would this tree be worth digging up and potted for bonsai (post air layers)?
Thanks in advance