Will gormeks defense down and wokong attack increase and combine together and increase the damage
Yes, of course.
Gormekk‘s def down is a Status ailment on opponents, wu makes an attack buff on your allies
For full reference I recommend this topic
But whilst we’re on this topic… Fire Wu Kong last!!!
If you fire Wu before your debuffers, you have a chance for the defence debuff to miss - you don’t want that, so you fire Wu afterwards!