Probably. Your opponent gets to choose the damage assignment order of his attacking creatures that were blocked:
509.2. Second, for each attacking creature that’s become blocked, the active player announces that creature’s damage assignment order, which consists of the creatures blocking it in an order of that player’s choice. (During the combat damage step, an attacking creature can’t assign combat damage to a creature that’s blocking it unless each creature ahead of that blocking creature in its order is assigned lethal damage.) This turn-based action doesn’t use the stack.
Example: Vastwood Gorger is blocked by Llanowar Elves, Runeclaw Bear, and Serra Angel. Vastwood Gorger’s controller announces the Vastwood Gorger’s damage assignment order as Serra Angel, then Llanowar Elves, then Runeclaw Bear.
Assuming your opponent wants to, he can easily assign lethal damage to both of your blocking creatures, resulting in all 3 creatures being destroyed for having lethal damage marked on them once combat damage has been dealt.
Since none of the creatures have first or doublestrike; all damage is assigned, then dealt at the same time. So the 5/1 Scorchwalker will deal its 5 damage (divided between the 1/1 and the 3/2) at the same time it receives the 4 damage from both of them.
Your opponent could overkill one of them by assigning all 5 damage to it, but that is an unlikely scenario.
that's really strange to me for some reason. I get it because how you guys have explained it, but it just seems weird that creatures deal the damage simultaneously. I always thought that the active player "lines up" how damage is dealt in terms of 1st, 2nd, 3rd, etc. I guess I just have always misinterpreted "assigns damage" to mean "line up blocking creatures" when it literally means "assign damage creature has to give". thank you.
When multiple creatures block 1 attacking creature, the attacking creature controllers gets to choose the order in which blockers will recieve damage.
Then when it gets to dealing damage he has to assign lethal damage ( lehtal being the creatures thougness minus any damage the creature has allready taken this turn) to the first, before he can assign damage to second ( and same for second to thid etc)
Lets say in your example he chooses Wojek Halbediers as 1, and Foundry Street Denizen as 2.
Then both players get to use spells and abilities before all creatures actually deal damage.
Lets say you use a pump spell then to give your halbediers +4/+4 making it a 7/6.
If creatures then proceed to deal damage, the Halbediers is first and the attacking players has to let the Scorchwalker deal all 5 damage to it. It can't change the order now he knows he can't kill the Halbediers.
At the same time, the Denizen and Halbediers deal a total of 8 to the Scorchwalker killing it.