Rejoice I shall!
Milwaukee: I don't know much about Milwaukee, but maybe something like Schooners or Bridgers. Apparently, Milwaukee was home to a bridge war in the 1840s and I think both of these names tap into that unique side of Milwaukee history.
Winnipeg: Black Bears is great, but I'd like to suggest just Bears: Winnie-the-Pooh was named after Winnipeg the Bear, so that'd be a nice nod to a beloved character while also staying fierce. Maybe the colors could be gold and red, just like the character.
Houston: I love the name Comets, but that's been done to death, so instead, I'll submit both Talons and Controllers, for the space center. The T-38 Talon is a jet used by NASA and Controllers for Mission Control.
Charlotte: Both Monarchs and Royals are great, but I'll go in a different direction, something I've been pushing for someone to use for forever: Firebirds. If you don't know, Charlotte is home The Firebird, a statue just outside the Bechtler Museum of Modern Art in Uptown, and it's one of the city's most famous pieces of art. It has an incredibly distinctive look, and is a symbol of Charlotte and its art culture.
[img]https://www.tripsavvy.com/thmb/1hZL0Fq0fieccuPd9t8Hvv1OOeo=/950x0/filters:no_upscale():max_bytes(150000):strip_icc()/744px-Firebird_closeup_Niki_de_Saint_Phalle-59127ae65f9b5864705412e2.jpg[/img]While it looks like a bird with long legs, it's actually a short bird sitting on an arch. (You can see the talons.) I think that this unique form and name could be a great source of a cool Charlotte name that doesn't use the royalty theme or uses Carolina, which I vehemently oppose outside of the Panthers.