You can EQ it if you want but you have to keep in mind that you won’t be able to change that after you record it. People usually EQ it after it’s recorded. If you find an “ugly” frequency (the one that really hurts your ear) you can cut that frequency and record your guitar but again it’s better to EQ it after because if you mess up your signal before you record it you can’t change it back. As for the EZ drummer i don’t think that you need to eq it because it’s already been EQ’d but that doesn’t mean that you can’t. You can always make it sound better but if you leave it just the way it is it will still sound good.
There are a lot of ways to make it sound better. EQ is your most important tool. With EQ you get rid of the frequencies that you don’t want, you make room for each instrument so that it sits well all together, you also boost frequencies that sound good for each instrument. Then you have a compressor which will make things thigher and it will give more energy but you must not over do it because you use compression only when it’s needed. There is no reason to compress distorted guitars because they are already compressed. What you can do it parallel compression on drums. Parallel compression is making a copy of a signal and then brutally compressing it, making it sound like shit and then you just mix that in with the original signal and it will sound waaaay better. So you have the original drum signal and you have a copy of that which is brutally compressed and you just mix it in with the original and that’s it.
oh and i forgot, at the master channel you can add a tape emulation so that it sounds warmer. There is an amazing free plugin called Cana Mystique Tape Machine and it works really well. It makes anything sound better. You can download it here http://www.canasanmartin.com.ar/plugins/
At the end of you master channel add a limiter to boost your signal to a commercial level so that it doesn’t sound really quiet