Hey guys entire campaign setting changed on me at session 0 so maybe you guys could help me out. Were gonna be playing the Strixhaven Module then my DM is going to connect it into the new Vecna module coming out. What I was wondering is if having more than one melee is super imporotant. 
We have a Fire Druid, Rune Knight, Life Cleric (super ranged), and Ranger (bow) 

Was wondering what you guys think would fit best here? I was looking at Paladin or Wizard. 
 

Forget about what you need, what do you want to play?   The Wizard would be the classic play, but if you do not want to play a Wizard, then play the Paladin.

If most of your party are ranged characters they will end up frequently caught up in melee. You need people on the front line, IMO at least 50% ratio or near so.

We played Strixhaven without a martial. It's not unusual for students to be really caster based at a magic school. We had moon druid, sorc (rune), sorc/rogue (shadow sorc), wizard (evoker), wizard (evoker). Oh, no wizard in the party at a magic school? I've always felt Strix was geared towards wizards, so that is a good way to go.  You could go bladesinger if you think you'll go melee. 

Now for VECNA...I don't know.

You can get by without a melee focused character in a party, but it really helps to have one.

And this is for any adventure, not just Strixhaven.

It doesn't need to be a martial character, but someone that can effectively fight in melee. If all your party are trying to remain at range to avoid all the disadvantage, what stop enemies from going to them and engage them in melee anyway? That's where a frontline character comes in.

Actually, I'm playing in a free one shot tonight and the three of us are not traditional melee characters but all are highly mobile: monk, bladeslinger wizard (misty step and invisibility), and an evoker of a flying race (me). Let's see how it goes. There are two spots left so maybe a barbarian, paladin, or fighter will join.