Hi. There is also a technique, called Recorderman technique, which allows you to record drums with two mics.
https://www.youtube.com/watch?v=8X_kMItRI2s (this was the first that came up, Googling it) 
This will give you a stereo recording, and you will have two mics to record the rest of the band.
Best of luck.

Zargg71
Hi. There is also a technique, called Recorderman technique, which allows you to record drums with two mics.
https://www.youtube.com/watch?v=8X_kMItRI2s (this was the first that came up, Googling it) 
This will give you a stereo recording, and you will have two mics to record the rest of the band.
Best of luck.

I've used this technique before and I personally tend to prefer the method I mentioned primarily because it is difficult to get the kick like most people want to have a kick if you use the Recorderman Technique.  
 
The Recorderman Technique is basically the Glynn John's technique minus the Kick mic and the snare mic.  I don't find the snare mic is necessary in the GJ technique, but the Kick really does help in most rooms.  More so than I personally think the side fill mic brings to the table.
 
Especially if you use a Mono to Stereo plugin like the Nomad Factory (or even better...the JST + Boz Labs Sidewinder) on the single overhead.  

I've done a couple projects like the OP mentions. It was easiest to rent extra mic's and I/O. Use the mixer for drums and send it as a stereo mix to sonar while putting the rest on their own tracks. The bleed will be unstoppable in the situation described so discreet inputs might not be that important. I typically set up for a live, off the floor, recording and then season the whole mix.
 
You won't get anything really professional sounding but you can get something that's quite reasonable and representative of the band.

In my humble experience the best thing to do if you do not want to rent extra mics and an interface is to use two rooms mics in stereo. Move them around and see what you get. I have often found that to be a decent sound and set up. That also depends on the room you are recording in and if it is a good room. I have a large space (huge) that I can use which allows me to set the mics at any distance I need to and find the sweet spot.  I actually almost prefer it this way instead of trying to mix all those mics. A garage may not be good for this though. Experiment and find something that works. You never know what you will discover. Try a room and a close. I guess the big obstacle to that would be if they are all playing at once and then the farther away you get the drum mics the more bleed you will get.

All good advice here Walk around the room, and see where you think it sounds best, and start placing mics from there. 
Best of luck.

Another quick question guys.. If I wanted to record all the audio for this project onto an external hard drive how would I do this? (I mean every take as I record it) 

You can direct where you want your audio stored by going to Preferences > File> Folder Locations > Project Files

garygml
Another quick question guys.. If I wanted to record all the audio for this project onto an external hard drive how would I do this? (I mean every take as I record it) 

 
I'm not hugely experienced in live recording so others may have better advice ... but ...
 
Use Comping mode and AutoSaves.
 
Comping mode will maintain take lanes. Be sure to do a final and separate save before editing (the real 'comping' phase).
Autosave is time or change based. (Else manual saves after each take). There's also versioning as per:
Preferences > File > Advanced
 
Mix Recall will provide you some recovery points at the mix stage.
 
Videos for Comping and MixRecall at:
https://www.cakewalk.com/...University/Get-Started

I've had to, on occasion, use one mic to produce a recording.  It takes a bit longer, but it can yield surprisingly good results.  Here's a post that summarizes the technique:  http://forum.cakewalk.com/FindPost/3055884
 
Hope this helps,
Paul

If you only have 2 channels then you are stuck with making a stereo recording. I can't see that these kids will want to go through the pain of layering each instrument track by track with overdubs. It is much harder for a young band to work in the overdubbing and building a song track by track environment. The song will turn out sounding way different than they are used to hearing it. A band plays as a unit and it is a shame to not record them live and multitracked. 
 
Pick up a Tascam us1800 for less $200 or for $300 the new us16x8. 
 
But your also going to need a lot more mikes. 
 
So with what you have best you can do is a LIVE stereo recording of the whole band which will take the right room and mike placement. ( note: A Tascam or Zoom handy recorder will work fine for this). 
 
The Zed 10 and your 4 mikes could be utilized to make a live "board mix" that's what I would do. 
 
Ch 1 - Left Drum mike  pan Left
Ch 2   Right Drum mike pan Right 
Ch 3   Vocals  
Ch 4   Guitar cab miked
Ch 5    Bass DI 
Ch 6   Keyboards? 2nd Guitar DI? 
 
It's USB output is only stereo , it is not multi track. And I beleieve it has sloppy drivers so best to just use your Focusrite and the analog outs to have better quality drivers. 
This would work best if you coulld remove yourself to a sound isolated location ( The back lawn? ) with some longer cables etc. Because your going to need to MIX the band live. If in the same room use headphones and it will take a few stop starts to get the balance. Play, listen, play, listen etc. Once your get a good balance all they need to do is play all their songs.