Baygo, I like the fact that you are so willing to put yourself out there looking for feedback. It shows me that you really want to serve your customers. It also shows me that you are not really sure who your customer base is. And what better way to find out than simply ask. IMHO you would be turning away an awful lot of potential customers with to strict of a dress code. My attire up there during the summer consists of a bathing suit or clean shorts, sandels and a decent t-shirt. How about just posting No Bathing suits. This could be a great little destination stop for groups on motorcycles as well. Think Bike Week.
As far as kids go this likely would not be much of a problem. A tapas menu isn't really ideal for children anyway. You may be over thinking this one. If it is an issue then maybe trying to keep families in that front room past the staircase would be the solution.
I would like to wish you the best of luck. I think it a great idea.
