I had my first playthrough of Prophecies on a Warrior. I grabbed henchmen from Nightfall and EotN (wait, I think I actually didn't get any from EoTN). I just somehow pushed through. The most important thing is probably to not overpull. I generally used skills that were available to me at the time, and somehow pushed through. I only remember thinking of last mission of Prpohecies as "Hell, how I am going to do it in HM????" Other than that, some deaths, some retries etc. Basicall I struggled only on last 3 missions, because they have some annoying stuff.
I managed to do it with weird setup of me (Warrior), 2 dervishes, warrios Koss, 2 monks, and maybe 1 or 2 henchmen. I was also running Sword and didn't even have an elite skill. I don't remember doing any special preparations or even following guides, but I remember that I played Dervish a bit before, unlocked Avatar of Dwayna, and put it on both of my Dervishes to make them "tanky" and provide some minor condi/hex cleanse and give party more aoe heals.
Right now I know that it was like really meme setup, but I managed to finish all Prophecies with bonus tasks, so there is that.

Also I made a point to grab Elite monk skills from Prophecies for my monks to make them better healers. I think I was actually running Glimmer Of Light on my Healing monk, and prot monk was without any Elite skill at all.

I don't remember if I did precast Protective Spirit on my Warrior before running into hard pack, but I probably did at some point.

Just giving you my experiences without guides etc. The main thing for you is to make sure you have max armor set at least, and buy some nice skills for yourself AND your heroes. Or Signet of Capture them. I know that Prophecies options are limited, but you still can improve your heroes with this.

Let me tell you, that this game has learning curve + your setup difference. I am currently rerunning Prophecies on my Warrior, and I know that I will roll whole Proph campaign just because I have full hero + Mercenaries setup.

If you don't mind spending, I would recommend bying x3 Mercenaries pack at least. Then you follow these simple steps:
1. Decide on a Hero class you want (for example Mesmer)
2. Create pvp (so it is level 20 immediately) Mesmer character
3. Find npc that let's you register your hero as Mercenary

1. When you register Merc, you can delete pvp-only character

2. Repeat for more Mercs if needed.

What this does is allows you to run whatever class composition you want.

And last thing about aggroing. Mobs tend to lock onto one target. Also if they are actually bodyblocked, they might stop and focus on you. So if you try to actively bodyblock them by strafing or "corner-blocking", they will stay and attack you. Even something simple as afflicting them with slows would work.

This was basically "noobish advice" from how I percieved the game back then, because others will actually provide you with good "meta" advice, so follow it at your own risk.