The first point is a cutting from the Penny Illustrated Newspaper dated 11 January 1873, which reports on the previous week's match at Kennington Oval. It states: 'The Londoners wore white jerseys with the City arms inscribed thereon in red; the Sheffielders red jerseys with the Sheffield arms on a white ground, so that each player was easily distinguishable.' This indicates strongly that a uniform strip was a novelty that season.
Second, the man in the top hat, middle of the back row, appears to be Charles Alcock. He played in the first of the three London v Sheffield matches that season but was then injured in the notorious 'hacking' match, so did not play in the other two. He was umpire in the March match.
Third, the weather. In the January game it rained heavily and there is no sign of wet weather here. However, in March there was a sharp frost so it was bitterly cold that day, and it is clear the spectators are wrapped up well.
Fourth, according to the match report in the Sheffield Daily Telegraph (18 March 1873), both teams were photographed before the kick-off. It was obviously an unusual occurrence for it to be mentioned in the paper.
Unfortunately I don't have access to good quality pictures of the other players to confirm their identity. But, given the caps worn in the international seven days earlier, could that be Alexander Morten in a black cap, sitting next to Arthur? He clearly looks to be an older man than the rest.
The London team that day (according to Bell's Life) was: A Morten (Crystal Palace, goalkeeper), CJ Chenery (Crystal Palace), AC Thompson (Wanderers), AG Bonsor (Wanderers), GHH Heron (Uxbridge), R de C Welch (Harrow Chequers), AF Kinnaird (Old Etonians, captain), RK Kingsford (Civil Service), R Barker (Hertfordshire Rangers), C Warner (Upton Park), AJ Heath (Harrow Chequers).