counting both single and team competitions. Somebody posted that it is 12-6 between Li Dan and LCW. Does that include all the events? or is it just for singles? Thanks.

Yes, all the events including team event like Thomas Cup and Sudirman cup.

Yes, all the events including team event like Thomas Cup and Sudirman cup.
did it include LD beating TH twice in 2006 AG?
did it include TH walkout in HKO as H2H?

correct if i'm wrong, the only instance where LD lost to TH is

2005 WC
2006 AG MS individual event
maybe 1 more i forgot

I read an article from China, that the head to head between Lin Dan and Taufik since the beginning of 2006 to present is 10 to 1 for Lin Dan.

Then Taufik defeated Lin Dan twice before 2006 and Lin Dan defeated Taufik in Surdiman 05, so adding all that together will give you the total of 11 to 3 for Lin Dan.

By the way, the current Head to Head between Lin Dan and LCW is 13:6 for Lin Dan if all the matches(incl. team events) are counted. 12:4 for Lin Dan if only individual matches are counted.