How to use multimeter to Diagnose ICs and other Board Components.

Unfortunately, what you seek is beyond the scope of a simple answer on this forum. There is a lot to learn but most if it you can do on your own if you put a bit of effort into it.

IMHO if you are going to be doing board level repairs as a business, I think you should be investing some time and effort to understand at least the basics of electronics. Once you understand what a resistor, capacitor or inductor (coil, choke, ferrite bead) does and how they behave, you will know how to test them and whether or not it can be shorted or removed.

This is a good tutorial on how engineers deliver clean power to IC's. This is very relevant as the majority of the passives on an iDevice logic board are there for this specific reason. There are several articles in the series and they touch on capacitors and ferrite beads (filters). Another good source of materials is ElectronicTutorials. There are also some good youtube channels such as Afrotechmods, AddOhms and of course the EEVBlog.