1 and 2) If you only want to pick exactly these Shadow Hand things, take Swordsage2/Rogue3/Swashbuckler rest. Swashbuckler has a great BAB, good hp and you get full sneak attack with Daring Outlaw. Check out especially the swashbuckler class variants in Complete Mage and PHB2 where you get better or simply different things for Grace and Dodge bonus.
3) kukri are fine.
4) No fighter needed since you get Weapon Finesse with Swashbuckler and you don't need the Martial feats due to swordsage.
Feats: TWF, ITWF, PBS asap, Dual Strike as soon as you qualify to be able to dish out good damage with standard actions only. Biggest problem of the build: High Wis for swordsage, high Int for swashbuckler. Str, Dex, Con needed anyhow... though you won't need too much strength due to Shadow Hand.
Edit: This build won't need prestigeclasses, but take a look at tempest lateron.