We have a 14x16 Northwest with the 5 foot porch. It's plenty big for 3 adults with cots along with a stove and table inside for hunting season. I too have bunk bed cots the kids sleep in and this saves a lot of room but admittedly, the kids were with us in the summer when we had no need to set up the stove. 5 adults I'm sure is possible with a 14x16 with the stove set up. Just might need to give up the table and rely on it being outside.
We have the velcro in floor and it's real nice. We kick our boots off under the porch and wear slides inside the wall tent and put down a couple carpets to make it warmer on the feet when you get up at -15C in the morning. Added benefit from the velco floor is it's kept the mice out at night. You can hear them scurrying along the sides at night trying to figure out a way to get in but they give up.
Heat from the stove one year melted a hole underneath the stove for the velcro in floor so that's a bit of a pain and now we toss a welders blanket below the stove as well as have them draped from the frames to reflect heat away from the canvas.
Good luck! Only downside to a wall tent is it's half a day to set up and half a day to take down, and you have to make sure it's dry dry dry before you store it away.