Newbie, technically challenged, diy question, filter/exhaust, smell

Like so many others, want to build a stealth cab. Pondering refrigerator. May just build box. I can find plenty of info on that, I have what may be a stupid question. Wouldn't be the first stupid question I've ever asked...so here goes. If there is a hole or vent for intake, does the smell not escape? If I'm exhausting with a carbon filter, do I need to vent to the outside of the house in order to keep the house from smelling, or can it just exhaust into my basement? Again, looking for ZERO odor. Everything else has seemed fairly easy to research thus far, I just can't seem to figure out whether I need a carbon filter AND vent to outside, or if the filter is enough. SCROG, personal use, maybe 4-6 plants? I think? I'd welcome any suggestions for build plans as well. Very detailed, very DIY for dummies. Thanks, in advance!

4-6 plants not an issue if you pick the "right" strains. Stay away from the "skunk" varieties. When i do my exhaust i either tap into a bathroom exhaust or if I am adding a separate exhaust fan I take the tubing off one of the bathroom units and add it to mine. So the existing exhaust fan now goes straight into the attic space and my new exhust now goes out the roof. Adding carbon does help and a few ONA help also.

If there is a hole or vent for intake, does the smell not escape?
With just a hole as intake, yes some smell can escape. This can be minimised if the hole is sited in bottom corner of the cab and exhaust in opposite top corner of the cab. It can be further minimised by using a seperate fan for intake and another for exhaust.

If I'm exhausting with a carbon filter, do I need to vent to the outside of the house in order to keep the house from smelling, or can it just exhaust into my basement? Again, looking for ZERO odor.
Ideally you would want to vent outside but you need to consider people passing by. Might a keen or nosy asshole pick up a whiff and turn columbo?

If you still have a bit of smell even with the filter check out an Ozone Jr., I have one and it works great. Also for a DIY intake filter go to my started threads and you will see one.