Just add the line /click Smartbuff_KeyButton to your follow macro. I'd suggest using a nomounted variable so it doesn't try to buff when you're 1000feet in the air.

Tank Macro

/jamba-team invite
/click [nomounted] SmartBuff_KeyButton
/jamba-follow strobeoff all
/run UIErrorsFrame:Hide();

Shaman macro

/click [nomounted] SmartBuff_KeyButton
/cast [nomounted, nocombat] Totemic Recall
/focus Kina
/follow focus
/script SetView (4); SetView (4)

Ret Paladin

/focus Kina
/follow focus
/click [nomounted] SmartBuff_KeyButton
/script SetView(4);SetView(4)
/cast [nomounted, nocombat]!Find Herbs