If you've got some patience, I would suggest building the computer yourself. There's a guide on which components should fit together here:
http://www.logicalincrements.com/
I built my own about two years ago and now it would be somewhat in the "Very good" tier. Never had a problem recording, video editing, design and some gaming as well.
I'll answer your questions according to what my experience is, but I'm no expert in this matter.
1. RAM: I think 8GB is enough, you can always increase in the future if you feel you need more.
2. GPU: I would get one, and I think the GTX 1050 Ti is sufficient for recording.
3. CPU: One with as many cores as possible. I have an IntelCore i5, but depending on what you do I'd save on the GPU and invest on an i7.
4. Storage: SSD is much faster. You can always have an HDD for your other things that don't have to do with your musical production.
5. Cache memory: as much as possible, again.
6. Hard drive size: 256GB is kind of enough for me, with another HDD. You can recycle the HDD from your old computer. If you only rely on an SSD, go for the 500GB.
7. It's a mix of various factors, the guide on logical increments is quite good.
8. I can't answer this question and I don't want to say something stupid.