I've read that monks can use the two-weapon fighting chain of feats if they wish with their unarmed attacks. Is this "officially" true?
It is. From the Official FAQs from WotC:
"The rules don’t come right out and say that a monk can’t use an unarmed strike for an off-hand strike (although the exact wording of the unarmed strike ability suggests otherwise), and no compelling reason why a monk could not do so exists.When using an unarmed strike as an off-hand attack, the monk suffers all the usual attack penalties from two-weapon fighting and the monk adds only half her Strength bonus (if any) to damage if the off-hand unarmed strike hits."
I myself thought this was not possible (due to poor wording in the rules). Of course, some feats like that you mentioned are obviously sub-optimal with "Monk/Two-Weapon Fighting".
If I am not mistaken the monks improved unarmed strike stats that their unarmed attacks are consider weapons. So this should make the qualify to use two weapon fighting.
Hmmm...so in other words, while I could take the feat and get the +1 to AC you feel that this would not be as good as some other feats I could take.
Actually, the feat you mentioned is not suitable for Monks with unarmed strikes (the feat itself states it); a lot of other feats, however (like Improved Two Weapon Fighting) are suitable. The problem is that some feats have a harsh BaB requirement (like Greater Two Weapon Fighting, for a third off-hand attack - requires BaB +11, so a Monk can take it from 15th level), others requires the use of physical weapons (like the aforementioned Two Weapon Defense), and others have some strange requirements that a Monk cannot have at all (like PFRPG feat Shield Master - that requires the use of a SHIELD, something that a Monk would never use...).
A Monk would really rely on Improved Natural Attack to be an effective Two-Weapon Fighting combatant...
Double Slice (+2 to off-hand attack)
Plese note that Double Slice, in the full description, says that you can add your full Stength bonus to the off-hand weapon damage instead of the usual half Strength bonus(in this case, unarmed Monk attack) (page 85). Probably, the brief description in the table is from a precedent version of the feat.
Weapon Focus (unarmed)
I would personally go for a 1st level Monk with 10 Strength and 16-or-more (the more, the merrier) Dexterity for a Two-Weapon fighting build, taking Weapon Finesse instead of Weapon Focus. The feats for this kind of build are really Dexterity-dependent (17 Dexterity for Imp.TWF, 19 Dexterity for Great.TWF), and since Wisdom is essential for a Monk (and Constitution is NEVER a waste), this pretty much leaves Strength with very poor bonuses - and so, better pumping Dexterity and taking Weapon Finesse (since now it CAN be taken at 1st level, because it has no more the silly "BaB +1" requirement that every 1st level Rogue hated so much...)
The problem with monks + two-weapon fighting is that monks aren't that great at hitting opponents anyway. For you're level 6 monk, you're already taking a -1 penalty for flurrying, so putting an additional -2 penalty on for two-weapon fighting is tough for a class that only has medium BAB.