I was wondering why they put Miss Croner in when they could have used Miss Miller, who seems relegated to a brief cameo character nowadays, although Miss Croner is a lot more wikid and sinister than Miss Miller (like tricking the kids into searching for a cat) but they could still do the funny "crazy old person" comedy. Also, they could then have the Chipettes move in, giving them their own "Dave" counterpart/mother figure (I like Dave). Seeing as they would be neighbors (Chippettes still in close proximity) although Miss Croner lives in the opposite direction of where Miss Miller lived in the 80's series. Speaking of which who lives next door to the Chipmunks on the opposite direction from Miss Croner?
Perhaps they wanted a bigger distinction between the 80s series and ALVINNN!!! so they created a new crazy old character while giving Miss Miller more for the "feels." Though, Miss Croner doesn't really replace Miss Miller as Miss Miller is still in the babysitter role. Looking back, Miss Miller appeared as a dominate role later in the series so it's possible (not sure how likely) the girls could have a similar experience and move from their treehouse. How interesting would it be if The Chipettes moved in with crabby Miss Croner?