I wouldn't recommend it at this time of year it's pretty cold outside there.
But whether or not it's appropriate is going to depend on each individual's opinion. There will be some people everywhere who think you aren't wearing enough clothing, but the majority of people won't care.
That's inappropriate unless you're working out or jogging. I know a sports bra is comfy, but why wear it like a regular top out on the streets ? I think that style was good back in the 80s, but I think bandeau tops are coming back. link