Could a [name]Constantina[/name] have Sia as a nickname? Or is it too far a stretch.
(Already know about [name]Connie[/name] and [name]Tina[/name] and [name]Stan[/name] as nicknames. )
I think it could work, although the letters are pretty spread out. I think [name]Tia[/name] or even [name]Nia[/name]/[name]Nina[/name] are more intuitive than Sia, though…
Sure. The Russian nn is Costia. Like coast-ya.