We have rubber mats in front of the stalls and near our wash rack ut not inside the stalls (theyre inside/outside stalls so its pointless) but I love having my mats in front of the stalls it makes it sooo much easier to get the wheelbarrow around and it keeps it generally cleaner around. If I had a REAL barn (haha) I would definitely want some rubber mats and bedding. I agree I like to have a nice amount of bedding for my horses. But I can't really comment much because we just put sand in their stalls once a month.
But as for your friend. I personally wouldnt invite her to the open house just because if she's "all knowing" she may spread dissent throughout, plus if she got really pushy towards others they may just be dissuaded from coming to your barn if they feel that she would be a nuicance around....but that's just me.