Hi there HLA76 and welcome to this forum! Congratulations on the birth of your son.
I don't think I can give too much help other than to say yes, I have heard Salmon Patches/Stork Bites referred to as types of 'flat' hemangiomas. But I really don't know if several different types of birthmarks in different places could be cause for concern for internal ones...I suppose as you have an appointment with the dermatologist anyway, it won't hurt to ask. One thing I would say is that I remember often worrying that my son's marks may be linked to some other more serious condition....but I guess that's all part of parenthood - to worry about everything! It's easy to say don't worry but not easy to do! Good luck at the dermatologist, let us know how it goes,