MSC

SO.

I want to start a synthpunk-ish band but I have some questions.

Essentially what I want this theoetical group to sound like is 3 Synthesizers making noisey sounds, melodies/harmonies, and drones to a drum machine and soft whispering/spoken word building up to loudness and some singing. I want it to be the lovechild of Stereolab and Moss Icon. Maybe some sampling, too.

Naturally, I don't know how to play any instruments and know very little about the process of making music. From what my very limited knowledge tells me, music revolves around melody, rhythm, and harmony.

Can these be accomplished purely with synthesizers? Can the roles of a bass guitar and a guitar be accomplished through the use of synthesizers? Drum machines would be used to act as drums. I'm going for an entirely synthetic sound that can go from being pretty to being harsh and aggressive.

Are synthesizers easy to learn how to play? What brands/models would work best with the kind of sound that I'm going for?

Freebase Dali

Well.. Yes, the role of the bass can be entirely accomplished on the synth and very creatively I might add, as well as a lead synth(s) that theoretically takes the place of a lead guitar/rhythm guitar depending on usage. Drum machines would obviously form the percussion section.
This is a setup that's common to practically any type of dance/electronic music. If you've got three guys with 2 synths and a drum machine/sampler and one of you singing, you've basically got a full on electronic live PA act. (Which are the best live experiences in the electronic realm, if you want the opinion of an electronic fan... as opposed to a single guy spinning records)

So you've got a great goal, but you need to start small. If you really know as little about making music as you say you do, you have a long way to go. Read up on tutorials, guides, tips, and anything you can get your hands on. But to answer your immediate questions:

Any synthesizer is going to be the same playability to you if all you're doing is pressing keys while you're of whatever level of musicianship you're at.
You should also know that there are two main categorical types of synthesizers: Modeling synths and Sampling synths. (Leaving out deeper level stuff like Subtractive synthesis and Wavetable and all that..) The former is harder to learn in a programming sense, but far more flexible in that you can create your own patches... while Sampling synths (those that use samples as the basis of their sound, and not sound synthesis) are more user-friendly and sound [subjectively] good right out of the box... but really lack in flexibility because you're stuck with whatever sounds the synth comes with.
There are both cheap modeling synths and sampling synths... and also very expensive synths in both categories. You really need to physically go to a music store and test out their synths and hear for yourself what you'll buy.
In either scenario, it's good to consider sound sculpting "externally" because it will be useful for a synth player either way. What I mean by this is external processing. Like distortion pedals, compression pedals, Wah pedals, Filters, etc... If you create yourself a nice pedal board for your synth, then you'll be able to further sculpt your sound beyond what's provided on your synth. And most importantly, it's compatible with live performance. Think of your synth as your guitar, and your pedals as your guitar pedals. Being able to operate both simultaneously is of key importance when doing live PA performances.

As far as what brands/models would work best for your sound... I'd say that if you're going for a punkish electro sound, get the most reasonably priced synths you can... but the best pedals you can. Your gritty sound will be far better served externally, and especially where you can control them manually. And make sure you don't all get the same synth. You'll want to get with your band mates and find synths that really appeal to you as individuals but compliment each other as a whole. Each synth is going to have its own sound and patches, so you'll want to use that to your advantage. Everyone having the same synth is only going to limit your options.
Think of it in terms of musical instruments. Your primary bassist will need a synth that places an emphasis on basses. Your rhythm melody instrumentalist and your lead melody instrumentalist can often change roles at any given time, so each person having a synth that fulfills both roles is important if you want flexibility. There will need to be someone manning the drum-machine/sampler unless you want your music to sound lifeless and static, so your drummer should be that guy. Obviously any one of you could be singing at the same time.

But let me emphasize this... ALL of you should take advantage of external processing. Even the singer should have vocal pedals. I don't mean this as a universal rule... but from experience, I'll tell you that if you want to dynamically change effects, it's better done with your feet and with an effect processor you trust to sound good. So with that in mind, remember to place some importance on that unless you don't expect your audience to mind the need for your band to stop playing just to change between delay and a flanger.

Anyway, if you have any specific questions, let us know. We'll do what we can to help, but you need to do this in steps. Because there really is a lot more to it.