does the ff+1+4 throw give frameadvantage?

and if so, how much?

IIRC it's +4.

But I'm not 100% on that.

From the looks of it the SIT2 juggle should connect.

wr1+2 doesn't guarantee anything, only frame advantage (a lot). It's a forced block which means your opponent can block any attack following.

After FC df+1,2,1, with the counter hit delay hitting, you can do a low damage juggle with FC d+1,1,1,2,1 (42 dmg) I think some of it's other variations work too for 40ish damage.

Checked it. I thought if FC, D11 worked you would be able to follow up with ws1+2,1+2 B! but you can't. I'll add it right away. By the way, I think you're confusing 2 moves: FC, D1112 and d21121_df1_d1? Or does FC,D11121 exist and I didn't even know?
While checking CH (FC,df1,2)1 I tried other stuff and came up with an immediate ws1+2,1+2. It hits every preset getup the comp can do. It'll always be the second hit that hits the opponent:
-getting up straight: BT hit which means a free 1+2,1+2, df141, 212 B!
-Rolling towards or away: instant BT B!
-Sideroll any way: knockdown for oki

I haven't tested against players yet so you might be able to quickstand before (ws1+2,)1+2 comes out but it's a good option nonetheless.

I'm fairly sure that FC D+1,1,1,2,1 does exist; just tested.

Anyways, I really like your option of the (WS+1+2,)1+2, 1+2,1+2 etc. combo afterwards. A full juggle on that hits 119 (non-counter). And yeah, even if it whiffs they'll either get hit or have to block...good stuff.

After d/f+2+3, you can also do the (WS+1+2),1+2 options. Pretty sweet and possibly more useful.

Its a little late for this, but the best not listed juggles I've found so far are:
CH ws2, uf+1+2, 1, b+4,1 B! b+2,1,2
and
db+2, b+4,1 B! d+2,1, cc, b+2,1,d+2 (This one has some weird timing)

I'm not on my ps3 right now. I'll add up the damage later