Wayne Junction/ Roberts Ave is the southern boundary for Germantown. Anything below Wayne Junction is considered Nicetown.

Johnson St. is considered the northern boundary.

Stenton Ave. is part of the eastern boundary, especially as it slices it's way south of Wister St.

Wissahickon Ave is the western boundary until you hit Walnut Ln. Then Germntown slices a bit farther west up to Johnson St.

But other than that, the boundaries you post are okay.