Ryder is the incumbent ODI opener from the New Zealand series against India. His 50-over form for Essex (369 runs at 92.25 in six innings with four 50s) has been compelling but recidivist disciplinary issues might make coach Mike Hesson and captain McCullum hesitant to gamble on a recall.
It's almost 10 months since Latham appeared in an ODI. He last played that form during the series in Sri Lanka where his 86 helped win a rain-reduced match.
The 22-year-old averaged 34.80 in seven innings at a strike rate of 94 during the List A matches in the UK but his consistent Ford Trophy record (286 runs at 40.85), sharp fielding and 'team man' reputation have earned kudos among his peers.
Neesham is more of a punt but could get a handful of opportunities opening in the 17 one-dayers leading to the World Cup. If the 23-year-old left-hander shows the technique to back his strike rate of 95 against the older ball, he'd offer further balance to a side teeming with all-rounders. Effectively, he'd pick up where Ryder left off.
Brownlie has stated his intention to transform into an opener, given the middle-order congestion. He could be given a chance against South Africa in October, or Pakistan in December.
He scored 347 runs at 69.40 in England, with a strike rate of 111 from seven innings at No 3.
The England tour also demonstrated left-hander Rutherford's limited-overs prowess. He scored 346 runs at 49.42 with a strike rate of 99.
Watling's ascension since taking the international gloves for the first time under coach John Wright in January 2012 continues. He led New Zealand A to seven wins in eight completed one-day matches in England, including three in a tri-series to equivalent development sides from England and Sri Lanka. Three matches were washed out.
The only loss came in a Duckworth-Lewis match against Sri Lanka A pre-tournament. There was also a draw with Surrey in the sole three-dayer.
A key driver to the 10-match List A component of the tour was establishing who can best help New Zealand win a World Cup.
Traditional statistics such as averages weren't used as the complete gauge to performance. Players were also assessed on target scenarios within games to see how they coped under pressure.
Watling stood out, with an average of 38.60, strike rate of 137 closing in the middle order and he also conceded no byes and took 19 catches with the gloves.