Yes it gives you a baby Eevee!
If you breed Ditto and Eevee than you'll get one egg and it will hatch into an Eevee but you can breed them as many times as you want to get more eggs and thus more Eevees.
A Dragonair and a Ditto will have a Dratini egg.
NO!
No.
you cant make an egg with Garatina.
Eevee's egg group is Field.
yes
Yes.
no, it can't
yes it can
yes ditto can breed with any Pokemon group except for those in the no egg group
yes,yes it can