Reddit mentions of Genes VI

You have a lot of questions that are difficult to answer without first giving you a solid grounding in what genes are, and how DNA works (which some of your questions suggest you don't yet have).

I suggest you try Genes - I've linked to version VI which is quite cheap, and for the basics not too far behind the state of the art. I think the latest version is XII, which has a few negative reviews claiming it's too advanced for undergrad-level genetics, so I've pointed you to VI which was my undergrad text and I didn't find too hard-going.

I'll try to give you some pointers, though:

1. and 2) No, position shouldn't matter, what matters is the sequence of base pairs in the DNA.
   
   
2. That can happen, if (simply put) the "core" (coding region) of the gene is swapped, but the flanking "control" regions are not swapped.
   
   
3. the number of genes doesn't affect much the length of the DNA. The length differ between species probably by random large-scale copying errors which expand (or reduce) certain stretches of DNA by duplicating them. Those stretches may or may not have genes on them. In humans as least genes represent a small % of the total length of DNA. I think you need a deeper understanding of what a gene is, and what alleles are.
   
   
4. the number of copies of a gene generally doesn't affect expression, but rather those control regions, and the presence of the proteins that recognise the particular control regions.
   
   
5. Dominance is actually a bit of an abstract concept. To take you eye example where a father has an eye and a mother doesn't. If the child gets one copy of their DNA with the "eye gene" and one copy without it, they will probably have an eye, because they have at least one gene. Here you can think of there being two alleles in the population, corresponding to a (large) difference in DNA sequence. The "eye" allele would be dominant over the "no eye" allele.
   
   I hope that helps a little, but keep reading! And youtube/google are not always the best sources. Perhaps a deep knowledge of genetics isn't needed for your purposes, but knowing the basics should help, and might give you some new ideas/directions.