Rookie new rear end new Drive shaft??

[67Jhdz]

I have a few ? can ya help a brother out

1- I am swapping my 6 lug rear end to a 5 lug rear end off a 85 chevy truck am I going to need to swap out drive shafts or can the same one work I currently have a 2 piece shaft now or is it better to have a single shaft?
2-I am going to replace the rear coils with airbags I order a c notch from CPP on ebay can someone put up some pix of air bags mounted not sure if i need to remove the rivits where the coil was before

thanks