You have learned to regain some of your magical energy by studying your Spellbook. Once per day when you finish a Short Rest, you can choose expended Spell Slots to recover. The Spell Slots can have a combined level that is equal to or less than half your Wizard level (rounded up), and none of the slots can be 6th level or higher.
Thus at third level you can regain one 1st level spell slot with a short rest.
To up our chances with Sleep, I'd recommend doing a surprise ranged attack first to reduce the bugbears' HP. Then Soledad can cast Sleep on them, and any that are left standing the frontliners can just take out. Leaving one alive for questioning would be a good idea.
To help with that, Constantine can cast Bless to help out with attack rolls. Any takers in particular want an extra d4?
Dragonborn do have a breath weapon - small, but dangerous. Whether it is fire or some other destructive force depends on their specific ancestory. You would have to ask Constantine for his spacific ability.
I missed a word in my post. We are aiming at the bugbears at the campfire not the fire itself. I can give the signal in game. to make it easy for the DM post if you are aiming at the right or left bugbear. Include the answers from those above you to make it easy.
Hornet: Right bugbear. Will give an owl hoot when time to shoot and cast spell.