Ok so straight to the point, i want to know the correct interaction between 2 things; one of that is the Effortless lace magic item (http://www.d20pfsrd.com/magic-items/magic-weapons/specific-magic-weapons/e ffortless-lace) and the Titan fighter archetype (http://www.d20pfsrd.com/classes/core-classes/fighter/archetypes/paizo---fi ghter-archetypes/titan-fighter), does the effortless lace reduce the -2 penalty of fighting with the extra sized weapons titan fighter allows or it is not a penalty derived from size difference?
And 2, the new slashing grace (http://www.d20pfsrd.com/feats/combat-feats/slashing-grace-combat) states that it can't be used if TWF or another hand is occupied, but what happens when you put that in a juggler bard? (http://www.d20pfsrd.com/classes/core-classes/bard/archetypes/paizo---bard- archetypes/juggler-bard-archetype)
can it now use slashing grace and TWF since is "hand free"? can it now use slashing grace while also wielding another object, a wand for example or a light shield?
I can't really answer your first question, but in answer to your second. No. You cannot under any circumstance TWF, even if you can do it with only 1 hand, much as a monk cannot flurry with slashing grace (despite it requiring only 1 weapon and working a lot like TWF).
And no, it can hold a shield, or wild a wand. The hand must be unoccupied, and is explicitly denied the use of TWF and flurry. It even denies Spell Combat, which uses it as an "off-hand" even though the hand is empty.
1 - Effortless Lace reduces the penalty by 2, as in the total penalty. If you get -4 penalty, it becomes -2.
2- He has a free hand, but nothing states that this hand is unoccupied, so RAW, no (ie, what Claxon said).
I agree. His other hand is definitely occupied (i.e. "busy or in use").