These are all good questions.
We do sell some carbon steel knives. The ones I recommended for you are stainless and won't be a problem if you get them wet. If you have a particular knife you like just ask and we'll tell you if it's stainless. Usually we list the steel type on the pages.
Usually care for all knives should ideally be use, wash, towel dry, put away. Not everyone does this of course but for you I would recommend stainless since these are gifts.
Storage is really based on the person's kitchen. Many people will use 1 of 4 solutions based on their own space and preferences. Block, magnetic strip, sheath and in drawer holder. If you get a good Japanese knife like the Kikuichis I recommended I would suggest you get them a gyuto with a saya for each one. The sayas are wooden sheaths that protect the knife so you can put it in the drawer. You can find them here on our site: http://www.chefknivestogo.com/sayas.html
If you think they all have blocks blow the sayas off and they can add their new knife to their block.
The magnetic strips are very convenient but require drilling holes in the wall of your kitchen so they're not a great idea as a gift. If you kids have them already they're good to go. Magnetic strips don't effect
the knife in any real way.