I will try to clear your confusions line by line.
Gaudiya Vaishnavas claim that they follow the supreme Godhead Krishna
They don't, They follow instructions of Krishna in Gita.
Krishna indeed said chanting of names is a sacrifice and one must always think about him while doing one's duty.
Amongst chants know me to be the repetition of the Holy Name(BG 10....
Atharvaveda 8.6.23 condemns the consumption of eggs.
Ya aamam maansamadanti paurusheyam cha ye kravih
Garbhaan khaadanti keshavaastaanito naashayaamasi
We ought to destroy those who eat cooked as well as uncooked meat, meat involving destruction of males and females, foetus and eggs.