Firebird is a great choice! Although I must admit I am partial to them since they were developed at the nursery I work at. The breeding/selection was done by Michael Yanny who was the propagator at the time.

Firebird often is top grafted at 4' to a rootstock because it is slow growing. This will give you that small tree that is totally resistant to scab, is very cold hardy and flowers reliably every year. The fruit stays a nice red well into the winter for added winter interest.

Is Camelot a good choice despite it being a bit larger? I like the pink and white tones.

I have no experience with Camelot. Other mini crabs we grow at the nursery are Lancelot, Lollipop, Cinderella. Not sure how they perform in Maine but they do ok here in Wisconsin. They can sometimes get some apple scab but usually not too much. Not nearly as resistant as Firebird will be. Of those mentioned above I am partial to Lancelot. It seems to have more vigor in our fields and will be a whole size larger than Lollipop or Cinderella that were planted at the same time.

Firebird rates as "excellent" for disease resistance for all 4 primary crab diseases - scab, fireblight, cedar-apple rust and mildew - which is impressive for most varieties of flowering crab. The best I could find on Camelot/Camzam was a "good" disease rating.

And disease resistance would be my overriding concern for any crab selection.

Thank you all for the feedback