Optional determination techniques in Atomic Absorption Spectroscopy I have tried to find information about this case but I couldn't find anything specific.

The key point of instrumental methods of analysis, is for the student to be able to know which one of the possible methods to use for a specific determination. As for me, that is not an easy thing to do because every method has its pros and cons. For the moment I am analysing AAS (Atomic Absorption Spectroscopy), and I simply cannot tell:

What's the reason that $\ce{As}$, $\ce{Te}$, $\ce{Se}$, $\ce{Ge}$, $\ce{Sn}$, $\ce{Pb}$ is preferred to be determined only by the hydrid method? $\ce{Pb}$ for example can be determined also with the other methods in AAS  

Does anyone have any tip, how to choose between methods if it's required for any element?

I replied with a similar question earlier about the mercury determination.
Remember this is "atomic" spectroscopy so it is expected that the "sample" is being totally ripped apart. So one "best technique" per element. 

$\ce{As}$, $\ce{Te}$, $\ce{Se}$, $\ce{Ge}$, $\ce{Sn}$, $\ce{Pb}$ are analyzed by the graphite tube technique rather than in a flame because the technique provides more sensitivity. 

$\ce{Hg}$ is an odd one since you use a cold vapor technique. 

Of course depending on the particular sample matrix what you might need to change.