Mulligans
General Mulligans
Pretty much any mana acceleration or low-cost card is nice in your starting hand. Elder Longneck is pretty much ideal, as with the coin you can often drop your first 5-attack minion on round 2. Cursed Discipleis another great early drop; it trades very well, and even if it is killed by a cheap minion and a hero power you're still 2 summons closer to free minions.
A quest druid taking advantage of the 4-cost card Cursed Disciple to generate two 5 attack summons; Oaken Summons at 4 cost generates 6 armour and likely summons a 5-attack minion (albeit in the case of the Elder Longnecks, a rather weak minion if summoned this way), while also accomplishing your goal of getting another summon for Jungle Giants.
Nourish is used primarily for card draw after Barnabus is summoned, as are the Ultimate Infestation s.
Edit – swapped some Defias Cleaner in to deal with some troublesome Taunt/Deathrattle minions.