In Survival Branch only can you

1. Use the Freebie Wool? and
2. Use the brown wool it gives you for completing survival? You could preserve it out otherwise but in my opinion that'd be a unnecessary added annoyance. Also it'd be nice to be able to use the Freebie, but it makes sense if you can't. It doesn't save much time at all if you can use it.

Eh, lets not use the freebie. The point is get everything from the Survival Branch. Feel free to use the vanilla brown wool, it still comes from the Survival Branch, thus its ok.

Is it faster to ship or nether to cactus? with or without keepinventory?

Probably faster to use a boat, but I never thought about that, maybe Nether is faster. Not sure what you mean for the keep inventory thing though, Survival has keepInventory off.

or maybe the map is small enough and nether can't reach