What is bhramcharya or 3rd percept? Is it only pertaining to "no adultery" for layman or as "no sex" for monk? 

If such is the case, why in ganika sutta it was mentioned as "path middle to celibacy and adultery" for ganika(female dancers)? 

Conclusion:: 3rd percept varies from person to person. It is different for one who has the capacity to "no sex", one having capacity to "no adultery", one who has the capacity to "no sensual pleasures", one who has no-capacity or livelihood depends on adultery-- so "middle to adultery and no-sex(celibacy)",......... 

It's main purpose is to enforce people of various livelihoods, various traditions, various spiritual-levels, various situations(incidents) to realize the cravings associated with "harmone-loss through privates, mental-exhaustance in sensual-pleasings, breaking-percepts, various-perceptions, sankharas, ignorance". 

Is above conclusion true? Yes/No then justify? 

(wholesomeness has essence and craving of never-dying.)
Abhramcharya means non-celibacy. Avoiding bhramcharya is not the 3rd precept within the Five Prevents. Avoiding abhramcharya is for monks or for strict followers of the Noble Path following Eight or Ten Precepts. 

As for Ud 6.8, it does not appear to be about celibacy but about attachments arising in the mind due to celibacy. In Ud 6.8 (Ganika Sutta), there are lay people involved in immoral sex. Then the monks became morally outraged by this and criticized to the Buddha those lay people involved in immoral sex. Thus the Buddha remarked: both the immoral laypeople and the monks disturbing their minds via aversion to immorality are both on the wrong path.