Question: How many Japanese suicide bomber pilots died and how many of them successfully hit ships during WWII? (according to the most widely accepted estimate)
Widely accepted depends upon your perspective. The numbers aren't precise because many Kamikaze pilots were shot down by enemy air cover, or AA fire before ever making a run at an enemy ship. Those still appear on Japanese statistics, but would not appear on enemy statistics. The other way around, some attacks occurred spontanously by Japanese pilots committing the ultimate sacrifice opportunistically. These attacks might be under represented on Japanese statistics but would likely appear on US statistics.
From U.S. perspective there were 944 attacks, 31% hit American Ships. Of those which hit American Ships 15% sank their American Targets. (Roughly 4.77% of the suicide attacks sank it's target). However that doesn't tell the entire story. A more accurate picture would also note that no capital America ship was sank by suicide attacks in WWII. The vast majority of ships sank by Kamikaze attacks were smaller vessels. Landing craft, aux landing ship, and destroyers.
Thunder Gods: The Kamikaze Pilots Tell Their Story by Hatsuho Naito
Altogether, 3,913 Japanese kamikaze pilots died in the "special
attack" missions against US and Allied forces during the war. Of
these, 2,525 were navy men, most of whom were between the ages of 18
and 20. Some of them were 17. The remaining 1,388 were army pilots,
most of them aged between 18 and 24. There are no accurate records of
how many Japanese servicemen died in individual, spontaneous suicide
attacks during the war, but the number was apparently significant."
Suicide Tactics: The Kamikaze During WWII By Gerald W. Thomas, VT-4
Although there may be some question about the exact numbers, the
damage done by Kamikazes is almost unbelievable. And the losses would
have doubled or tripled if the invasion of the Japanese mainland had
been required for surrender. All indications are that suicide tactics
would have been an important part of the final Japanese defense.
Japanese Special Attack Damage Inflicted on Allied Navies by Ship Type
*Special Attacks means Kamakazi
Ship Attacks Hits %Hits Sinkings %Sinking Hits
Battleships 37. 12. 32%. 0. 0%.
Cruisers 42. 15. 35%. 0. 0%.
Fleet Carriers 30. 10. 33%. 0. 0%.
Light Carriers 10. 2. 20%. 0. 0%.
Escort Carriers 39. 15. 33%. 2. 13%.
Destroyers 303. 92. 30%. 12. 13%.
Aux Landing Ship 428. 121. 28%. 25. 20%.
Transports 55. 29. 52%. 6. 20%.
Totals 944. 296. 31%. 45. 15%.
Effectiveness of Japanese Conventional and Special Attacks Against Allied Aircraft Carriers
Method %Damage Avg Weeks Repair. Avg Wks Out
Dive Bombing. 40% 0.3 0.7.
Sub Torpedo. 100%. 10 12.4.
Air Torpedo. 100%. 10 17.5
Air Special. 70%. 1.8 4.3.
And if you're interested:
Japanese Special Attack Aircraft Sorties During the Okinawa Campaign
Source: Steven Zaloga, Kamikaze: Japanese Special Attack Weapons 1944-45