I have quite a experience with lite sorc running Baal, have one doing it right now. I will tell everything I know to help you.
First of all,
equipment.
My equipment is like this:
Griffon with lite facet
Some crafted amulet with resists and 75 poison length reduction
1.07 Arkaines with
[email protected]
Hoto
Spirit shield
Arachnid Mesh
Frostburn
Rare boots with resists and 10 fhr
2x beta bkwb rings
Switch: CtA + Spirit
Inventory: 8 lite skillers, Tome of identify, Cube and rest are resist charms, so no free space in inventory for me. I don't need it anyway.
Merc: Infinity, Fortitude, Vamp. Gaze
My goal is to have 75 lite and fire resist, also high poison resist, high enough mana to drink random pots from ground, usually 1 per run. Idea is to run without going to town at all.
Since you are using Insight or something, you will have a lot more mana, and since you will use ES, SoJs are better choice. Also Mara's for you.
You can use different equipment, with better DR%, with some absorb and such things.
Now,
about your questions about dangers.
Souls are not really problematic. With near 3k hp and 75 lite ress, you can pretty much tank their projectiles to some amount. Since you will use ES and high mana regen, I believe they wont even touch you. At least at players 1 when you will run alone. At higher players settings, they probably might hurt your mana a bit I guess. Use absorb if you want, but check is it really necessary, I believe they won't be able to hurt you at all. When they shoot at you, just walk to the side and shoot back, most times they wont even hit you if you do this right. Don't know how hard it is to deal with them without infinity, but with infinity you can telestomp them if you want to. Just beware, they might take down your mana.
Stygian dolls are ONLY dangerous things in whole Baal running thing. If you will die, you will probably die from this guys. On players 1, they don't do much damage, however group of them can kill you. They are most dangerous when there are many creeps in throne and they are among them all so you don't really see them. Be careful of situations like that, rather teleport at clear area and shoot at creeps than standing among them and shooting. If dolls are there, you will notice your HP will drop.
With ES, I believe they will hardly touch you even when in group, only thing you should beware are mana burn packs around so you can have your mana intact. With mana and ES, dolls should be piece of cake, you can probably tank them no problem. But rather don't ofc, they might be a part of manaburn pack.
Safest way to deal with dolls is to tele at clear area, then WALK away a little from your merc. Let him tank them while you kill them with Chain Lightning. They fall no prob. If you are surrounded by them, don't panic. They are pretty much harmless with their daggers, only explosions are dangerous. Just tele out, don't kill them in panic.
Now, when throne is clear, let the party start. Players 8 now ofc.
How to kill minions in most effective way:
This is something I've been researching for some time. And I found my answers about how to kill every minion pack at most effective way. If you discover something better, let me know.
Wave 1: devilkins
Stand next to Baal, when you see he will throw them out, start Chain Lightning. CL them to death. Fast and easy.
Wave 2: mummies + skellies
Teleport at portal where Baal is standing, that way you are as far from the action as you can be.
When you see Baal will throw them out, cast ONE Chain Lightning so they get hit when they land. Immediately start spamming 3-4 Static Fields, and then finish them up with Chain Lightning. CL is better than Lightning because skeletons spread out, and with CL you usually take down whole pack no problem very fast. When it seems you killed them all, tele a bit through throne room in case some mummy revived something to kill that thing fast.
Now cure from poison if you have to via potion or visit town or drink heal potion to neutralize it.
Wave 3: travincal dudes
Same procedure as in wave 2. Tele behind Baal, one CL when they drop, 3-4 Static, CL to finish them off. If boss dude is resistant, then tele down from Hydras (they will throw Hydras at you, but they wont be able to hurt you with ES on) and kill him with Lightning or wait for a merc to kill him. I do it with Infinity so he is never immune, so just let your merc to kill him.
Wave 4: meaty dudes
Now, something new. If you stand next to Baal, this dudes will spread out cause of massive pack they are making. To avoid this, you should position yourself somewhere between Baal and exit of throne room. Like, in the middle of throne room more or less, probably a little closer to Baal. You will figure it out. When you see Baal will drop this wave, tele at that point so merc will be there with you.
Now, Lightning at them once or twice, then 1-2 Static Field, then kill them all with Lightning. This way they wont really spread out, they will come at you more or less in a line, so Lightning will be devastating. Static Field makes things faster even though you will kill them fast anyway.
Wave 5: Lister
Now tele behind Baal again. This time its important for your merc to be with you up the stairs because he will die otherwise. If merc is tarding around, tele behind Baal when you see that he will drop Lister and co. Now, Lightning once that will hit them when they drop down, then 3-4 Static Field, then finish the job with Lightning. You will kill them fast.
When Lister is lite immune, I suggest you park him out if you go for a Baal.
I don't kill Baal at all cause you level up faster if you just s/e after you kill Lister (or skip him entirely if he is lite immune) and go again than waiting 12 seconds for Baal to go into his room and then another 20 seconds to kill him there. So, if your goal is to level up, skip Baal entirely until high level, something like 96+, then Baal is profitable to kill xp-wise. If you are in for an items, then park lite immune Lister and kill Baal at p3.
I don't suggest using any prebuff memory stick, it's not worth it. Basic ES will be more than enough to protect you from Souls and Dolls. As you will practice a little, you will notice minions are superboring because they can't even hurt you (unless you count Hydras and poison in).
So max block is totally wasted as well, don't ever go for it with lite sorc. Learn to play her like this, it's not like any monster will be able to actually slash you or something.
Now, numbers. I don't kill Baal at all. So, my running times are at ~115 seconds. This means with Baal included it will be something like 140-150 seconds total. Don't know how long will it take without Infinity.
Damage is around 40k maximum with this equipment.
If I missed something, ask.
EDIT
I did miss something

If you get amplified, take Dolls dudes seriously. Just tele to clear area, walk a little from merc to let him tank them and kill them.
To remind you.
When you encounter multiple packs of stygian dolls at throne: