not too sure about the fusebox but i would use the one that came with the engine if you have it all. it might even install in place of the other one like it was meant to be and if its the same fusebox you could probably just switch the connectors over and use the stock box from your yukon.
your stock vortec fuel pump will work
either t-c will work but they might have different stall speed's
yes you can get the fuel filter fitting to go with the hard line, but i would personally just use high pressure fuel hose for ease of placement and replacement