Does MS Dhoni have the highest average of those who batted at No. 6 and above for India?
And has anyone played more international matches than Dhoni and taken only one wicket or fewer?
Remarkably, it is true: MS Dhoni batted in the top six in 30 innings spread across 22 Tests, and averaged 55.08 in them. Next (given a minimum of 1000 runs) is Vinod Kambli, with 54.20, ahead of Sachin Tendulkar (54.12), Virat Kohli (53.94), Rahul Dravid (52.36), Sunil Gavaskar (51.02) and Virender Sehwag (50.23). Note however that the 1000-run qualification is important, as Mayank Agarwal has so far scored 974 runs in 11 Tests, at an average of 57.29.
You're right that Dhoni took just one wicket in international cricket - he bowled Travis Dowlin to reduce West Indies to 57 for 5 in a one-day international in the Champions Trophy in Johannesburg in September 2009.
You're right that Chetan Chauhan, who sadly died last weekend, held that record for a while. He finished his Test career with 2084 runs, and a highest score of 97. That was the record until Shane Warne passed it in March 2002: he finished with 3154 runs and a highest score of 99. Chauhan still lies second. Among current players, Niroshan Dickwella of Sri Lanka has 1921 runs, with a highest score of 83 - so he might yet move up the list (or, as I'm sure he'd prefer, remove his name from it).
You're right about Glenn McGrath, who inflicted 104 ducks in Tests, just ahead of Muttiah Muralitharan and Shane Warne, who were both responsible for 102. By the end of the second Test against Pakistan, Jimmy Anderson had 98, with Dale Steyn next on 83.
Australia's Bob Simpson became the first captain to score a triple-century in a Test, with his 311 against England at Old Trafford in 1964. But he started a trend: no fewer than seven other skippers have done it since. Brian Lara tops the table, with his 400 not out for West Indies v England in Antigua in 2003-04. The other triple-centurions when captain are Mahela Jayawardene (374 in 2006), Mark Taylor (334 not out in 1998-99), Graham Gooch (333 in 1990), Michael Clarke (329 not out in 2011-12), Younis Khan (313 in 2008-09) and Brendon McCullum (302 in 2013-14).
"The list of both openers out first ball in a Test innings misses out on the first such instance - Percy McDonnell and Alec Bannerman of Australia against England at Old Trafford in 1888, a match which lacks ball-by-ball details, as mentioned in the column." This does seem to be true: it appears that Bannerman fell to the opening delivery of the second innings, from Bobby Peel, and McDonnell to the first ball of the next over, from George Lohmann. Australia were soon in disarray at 7 for 6.
Steven Lynch is the editor of the updated edition of Wisden on the Ashes