Buddha Aditya Yoga issues and Combustion

[Guest guest]

My question is:

 

a) The B-A Yoga (Sun/Mercury together in same sign) keeps your force

for itself or this yoga is sensible to the position of both the

planets in the signs/houses, the funcional strength/weakeness of the

sames and of the placement of ascendant birth chart?

 

b) The Sun/Mercury combustion is enough for the cancelation of Buddha

Aditya Yoga or no? The Both effects can coexist in one same map?