Harry's older brother Arthur (abt.1878) is probably at Coleshill in 1901:
Piece 2894, Folio 96, Page 1
...living with his uncle Mark Nicholds. He's shown as born at Brownhills which is near Hammerwich on the opposite side of Watling Street (and where they are living in 1891). Harry's mother Emma was born at Coleshill.
Harry's brother John is probably at Brownhills in 1901 with his wife and mother in law:
Piece 2666, Folio 65, Page 20
Possible births for Harry:
Sep 1881 Walsall 6b 704
Hill, Harold Harry
Jun 1882
Hill, Harold Walsall 6b 764
(Brownhills birth could be registered at nearby Walsall).
William as you know may be the person listed at Leamore in 1901 shown as b Essington.
Hope thats some help at least, no sign of Harry on 1901...yet

Paul