1) when rex uses his 1 pip and a unit splits fire can he add his weapon two both pools?

2)when a unit splits fire using a heavy weapon, given my fire supporting unit also has a heavy weapon am I able to split the fire support as well?

1/ Red can support both

2/ no the unit can only fire support once then flips it's order token, and therefore cannot fire support again, so you fire Support with your heavy or with a standard weapon , but you can't split fire the unit fire supporting (also it isn't technically attacking)

I hope FFG puts out an official ruling on question/toic #1 in this thread. We have debated this topic several times in my local group.