A giant poisonus snake can make a good job with 10 ft reach and poison boost to damage, unluckly being a small race he cant use reach weapons for what i understand, but a bow with shapeshooter is fine as well and it still allow the snake to make the help action (from lv 7) and get lots of OA (and till lv 7 thats the one thing it will do except carry the ranger and at low levels attack when the targets are not resistent to poison, as it should be better than the ranger attack), while the ranger shoot with his bow (or croossbow if at lv 8 it go for crossbow expert too) from 10 ft, its not a safe distance but anyway behind the tank and the frontline.
Uhm.than for play with advantage is better a no flying creature.
