I have a Boom Vader, and did the carb upgrade already so the only hose I left remaining is the crankcase breather hose (
https://mymotorcycleblog.com/boom-va...cc-grom-clone/ ).
IMHO:
Point is, if you have not done any upgrades, which it looks like, if you found a disconnected hose coming from the engine case, and found a open plastic nipple on the air box without a hose, you might have done a great job deducing how to fix it. I suspect if it's a was the straight hose from the crankcase, it was the vent.
You might not have any worries.
Except that stock chain, those stock engine mount bolts, oh and the stock carb that likes to just drop its fuel bowl dumping gasoline and leaving you on the side of the road, etc..... oh sorry having flashbacks. I'm sure you will be ok.
Congrats on the bike, I love my Boom Vader, did very minor upgrades and replacements of parts for better material and the bike is fun.
hth,