The advantage of having your own house is that you can remodel it anytime. I think the decision should come from you jleeds. This is your chance to build your dream house.
Metal pole works best since you need to put up a 12ft washing line pole. Just make sure that the fence posts are set into concrete bases and there should be a wooden panels in between.
Having that 7" depth is still feasible as long as there is proper support for the metal tubular frame like the hard cemented foundation. And also, make sure that the swing is for the children only. Don't let the adult ride on it.
