I hatched one of her eggs before, and it was a Wynaut. I'm assuming they are all baby Pokémon.
Yes.
Wynaut is a baby Pokémon that the old lady gives you. He is unobtainable in the wild and is referred to as a Gift Pokémon.
You can then receive a Togepi egg from her after beating Groudon / Kyogre.
Hope I helped!
Source: Serebii
Yes, she gives you baby Pokemon... BUT she gives you TWO eggs. One Wynaut and a Togepi.
Source: http://serebii.net/omegarubyalphasapphire/gift.shtml
Yes Actually, she only gives you one Pokemon egg, which is Wynaut Source