looks like you're trying to take one too much at once. I posted an idea of what a nine month student of mine would be working on, but that seems to have given you more questions than answers. I'll try to answer some of the questions you asked above.

The difference between a major and minor scale is that the third degree of a minor scale is flattened by a semi tone (if you play a 1 octave major scale, but drop down the third note you play by 1 fret, you're now playing a minor scale).

Pentatonics are the easiest scales, as they only have five notes. You could use E minor pentatonic to solo over a chord progression in an E minor key, but a riff ending on a particular note doesn't mean that the riff is in the key of that note.

I understand that lessons are expensive, but I really think you should have 1 or 2, just to join up the gaps in your knowledge so you're not confused. Either that, or buy a beginners intoduction type guitar book, and work through it from the beginning.

I'm not saying you're rubbish or anything, but if you keep trying to go forward while not understanding some of this stuff, it'll make it harder for you to learn.

If you have more questions - be specific and ask them one at a time.... it'll make it easier to answer you.... :D