Indoor Moving under the stairs

[Keenbutcher]

So I've had 3 plants outside for roughly 60 days and now the weather is getting cooler and damper I was gonna buy a small 0.5 x 0.5 x 1.0 tent(as my girls are quite small) and put them under the stairs, my question is will there be enough air in there and will it get too hot? I've got a 4" inline fan from a previous grow so air exchange shouldn't be a problem.
Check my grow out in the outdoor section for pics

cheers AFN!