Apparently you have an early version of the pack, and for the clicks we sincerely apologize.  Those clicks had all been fixed before release but for some reason one of the zip files never got updated.  Do you remember where you purchased the pack?  If anybody has a version of the pack with clicks please email our support with you receipt of purchase and we will set you up with the updated pack that has all of these fixed.

That's nice to hear! I got it from Loopmasters, I will be contacting your support about it.

Congrats for the gig! By frequency range I was referring to the fundamental frequency. Like Marrow said, if it's low enough it's usually classified as a bass. The harmonic content is not that relevant, since even a sine wave can be a lead.

Yeah it's kind of hard to give any advice, other than make sure you have the latest version of OTT and FL is possible.

You're trying to do too many things at once. If you have never been in the kitchen, it's probably not a good idea to start by making three-course meals.

To practice writing melodies and chords, write melodies and chords. Take a sampled piano or anything else that sounds good (presets are your friends) and just practice writing music. Rewrite other producers' music and create variations - this is what will eventually fill your brain with musical ideas. Also, from these practice sessions, you can build up a library of simple piano-based tracks, from which you can then draw ideas when you practice the producing part.

And I'm not saying you shouldn't practice your sound design and mixing skills. It's just better to focus on different skills in different sessions; divide and conquer. If you're not very experienced with writing music, try to make simple, rhythm based tracks (like techno or bass house). When you only have to design/select the drum sounds and a bass, suddenly the complexity of the task becomes much more manageable.

Finally, I get the impression that you should go deeper in the analysis of other peoples' music. Your ear is not really there yet if you can only tell a melody from a chord. And if you really spent time analyzing tracks, you should have plenty of ideas/reference material on when to use a pluck synth. The same divide-and-conquer principle applies to analysis as well: don't just mindlessly label things in a track and call it a day, but instead take some time to focus on transcribing rhythms and melodies, picking up chord progressions, and remaking sounds.

Here, there and everywhere. My drums usually comprise 30-40 tracks

Damn! Terry Bozzio would be proud! 

I follow pretty much exactly the same formula as Mussar... In electronic stuff, kick and snare centered, hats and cymbals wherever they sound good. For example, I might have a hat groove with three samples, where two of them are panned hard to different sides, and one (fairly) centered sample plays quieter offbeat hits. When the side hats hit at the same time, you get a nice stereo effect, and alternating them makes the groove a bit more interesting.

A powerful CPU is the #1 thing you will want. Even 8 GB of RAM is enough unless you use heavy sample libraries, but in that case it's better to pick a computer with a RAM extension slot. Also, you probably don't want the smallest screen.

Note that a hard clipper is a limiter, with zero attack and zero release. You can use it for reducing peak levels just like you use a limiter. The benefit of doing this with a clipper is that you reduce the overall loudness as little as possible. It's a great tool, and simple as hell to use, because you only have one parameter to adjust.