Types of wire...

You've asked a lot of questions, let me try to unravel this for you.

Solder will be sold as solder, so don't worry about that. If it is solder, it will say that. There IS silver wire that has solder in it. (I think) But it will say so.

Silver plated wire is MUCH different than silver filled wire. Silver filled is a weird name for a copper wire which has a heavy layer of silver on TOP of it. Not inside it. It is a superior product to silver plated wire, which has much less silver on it. Silver plate does not hold up well.

Then there is a wire which is copper that is coated with a silver color. That is like Artistic brand wire. It contains no silver.

Silver tarnishes, but it does not turn your skin green- that's copper. Gold takes for ever to tarnish. Both are easy to clean and polish. I would NOT spray them or even copper with anything. Although, some people do spray pure copper.

If I were you, I would look into silver filled and gold filled. The cost is much less and it is good wire with a high content of precious metal. It works well and wears well. It is more expensive than coated wire, but infinitely better. I think you mentioned in another thread about a couple special projects. If you needed just a little gold colored wire, buy just a little gold filled. You can buy small amounts.

Other than that, I would suggest Artistic brand coated wire as possibly the best coated wire. However, I would never use it for a special project. I think I used it one time, just to try it, and I didn't like it.   

Edit to add- I think Orrum mentioned Paramore wire in another post. I have tried parmore and artistic wire. It seems there are 2 camps of people. I preferred the artistic wire. However, I don't like either for decent jewelry. It nicks, the coating can get nasty looking, the working characteristics are not good. Wherever it scratches, nick or gets tool marks, the copper will show through and oxidize- sometimes turning green. Same as with the cut ends. You should always hide your cut ends.