Re: 3char Synergy
{...} i cant be 100% sure that the pally will always be online when i am. {...}
Player preferences and how often you're going to be together vs. solo are really too important to your questions for us to give good answers for you!
But assuming, from clues dropped, that you need to solo, don't have any wealth yet, will play more than your friends, but want the group to work well when you're together (all the way to Ubers)
and that none of you care which classes you play (so that all of us can recommend any combos we want)...
Start with the primary player being a Summoner. They ramp up fast with little gear investment. They MF pretty well vs. non-Act bosses. The Trangs set is good gear to aim for and costs less than 1 HR on trade forums here. They support party play really well (summon builds don't need tons of skill points, so you can utilize Curses easily--my advice: avoid the bone tree apart from CE). Some people find them hard to solo vs. act bosses (but you're going to have friends so I forsee no problems).
If one of the three of you is a Summoner then I strongly recommend another be an Enchantress. The gear for that is cheap (weapon switch +3 enchant staff shopped for and socked/runed to Leaf is trivial) and a Demon Machine + Razortail (again, cheap) make the build quite playable in the field and (imho, ymmv) quite fun.
If, of the three of you, two of you can reliably get together, then playing the Necro and Enc together is a cakewalk (imho
before you start enchant@18 and get your first point in Fire Mastery make a detour to put your intended build total of points for Static Field in early, which will make you/Necro level in norm/nightmare much faster and is too often neglected in Hell)
Of course, as others have mentioned, having a Barb (max BO) is very useful for a group, making play pretty forgiving (esp. vs. Ubers, who can one-hit-kill chars with low HPs). With a protective necro army the Barb can focus on MF gear and horking corpses behind the lines (Find Item) to help you all get wealthy faster. Once you do the Ubers the necro will neutralize the field while the enchanted barb goes toe-to-toe with crushing blow to take down the Uber (just in case the Barb's ego is bruised by not being super vital in normal play, just remind him he's the the Boss man!)
BTW, when you're poor, aiming to make a Lawbringer for someone in your party to have on weapon switch (probably the Enchantress) in nasty undead spots is a helpful, typically overlooked, trick (Sanctuary aura, knockback of all nearby undead every 2 secs).
I've done play duos of nec/enc in both classic and LoD back in v1.10 and they're so good it rather surprises me that more people don't recommend it (I imagine they don't realize that solo play of the enc can also be fun, although your practical MF runs are a bit different than what most people are used to)
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