Haven't had a chance to read the whole thread, so maybe this was suggested already, but...

Your mention of the kitten playing in the coal scuttle brought to mind Silas Marner and the foundling child Eppie: remember when he tried to punish her by shutting her in the coal hole, and she came out covered with soot and thinking it was a great game ("Eppie in de toal hole")?

So my submission for a sooty foundling-kitten's name is Eppie (as I recall, in the story, it was short for Hepzibah).