@FinalCatch
Hey there!
Welcome aboard and Enjoy your 'munda!
1)
Nope, all hits happen at the same time. So, for example, you Bolter someone with Rapidfire which gives you "3 Bulletholes" and a hit on the numeric die.
Then you roll 3 Woundrolls with S4, as the bolter says. Let's say one doesn't wound, the other two do. Then you make 2 Armour rolls, one for each hit. Let's say both go amiss. Then you have two bullets going through with 2 Damage each, so you roll 4 Injury dice. (Assuming the Target had only 1 Wound to start with)
2) Those two attacks also happen "simultaniously", in the game. You can either roll different coloured dice, or roll one shot after the other, but in regards of game mechanics, they happen at the same time in the same conditions. (Like the target being "standing".)