Actually, whether or not she has to summon him doesn't mean she's not married. That's just a mode of transfer. Married or not. There's no rule stating if she or anyone's married to a dead guy that they don't have to use any ritual. Besides, in the episode How Green is My Gallery. It seems Beetlejuice just lets her believe she has to say it three times. As he seems to have been watching her while she slept. "Beetlejuice, what are you doing here?" (though in her dream she did end up saying his name three times) there's another episode where he just jumps from his world into hers w/o the need of her saying anything, in fact, she was in his head the whole time, but didn't say his name three times.

As for the ring, she is in fact wearing it. lol - Check it out yourself. On the first episode, when Beetlejuice pops out and dances with her, notice-its on her left ring finger. After that it'll be on the right ring finger. This is actually significant, as her mother, married to Lydia's father, is wearing her wedding ring on her right ring finger as well in the movie and several times in the TV series.

Not to mention, wearing the wedding ring on the right hand is a French custom. Which is ironic, as for some reason, the writers highlight that Beetlejuice is rather very fluent in French in the episode where his skeleton separates from his body.

As for age. There is evidence that the writers might of meant for her to be older, such as when her relatives came to visit the first time, and she mentioned not wanting to see them, but wanting instead to see the 17 year locus, "I've been waiting to see them my WHOLE LIFE" which, might imply they wanted her to be possible 17 originally. But do to the censors that were obviously giving them a hard time and that the writers and artists clearly had issues with. (Miss Goody Two Shoes character that highlighted this fact) So in fact, she might of meant to be older.

And as far as breasts size and age, well, that's not always distinguishing factors. As the writers/artists seem to have made this point when the relatives of Lydia came to visit. Her Aunt apparently has no breasts and her Uncle is rather short, around her size more or less. So she might get a little taller, but not alot.

And if you notice, the aunt seems to wear the clothes as Delia from the movie wore as well, and the mayor (last episode) is based after Delia's agent from the movie as well. A few more fun facts.

More fun facts to come, I got millions.