The first few heads I did, I was concerned about the head being wet and screwing up the bearing edge ply. The reality is that by the time you get to that point the head is far from dripping wet - it's hardly wet at all. The conclusion I came to was that there's no reason to be concerned about it. I don't use any oil on the bearing edges. It's not a problem although before you do it you will think it might be, or at least that's how I was.
For the bottom heads, the heads are called "slunk". When the slaughter cattle for the meat industry (where all the drum heads come from) they have some cows that are pregnant. Those fetuses are the source for bottom heads. Since those fetuses have never seen light the skins are see-through. The reason Remo snare bottom heads are clear is to look like that. The whole thing is incredibly gross. The best source for slunk heads is used off of eBay, although they are somewhat rare. I bought a few 15's and cut them down to 14"s, that seems to be the poor man's best angle. Jeff Stern sells them new, and so does Rob Cooke, so they aren't hard to find, just hard to find cheap!
I haven't found that calf heads need any care whatsoever. I don't loosen the head after playing. If I went into a really muggy environment and had to tighten the heads, I'd loosen them back down when I went back to the normal environment I'm normally in, that seems to make sense. But, as a matter of course, loosening them after playing - no way. I just play them and don't do any maintenance. My kick head is from the 1940's and it's had no maintenance.
Using tap water is normal, that's all you need. Hawaiian water is probably slightly better though... :)
I have a really hard time changing the plastic bags in my kitchen garbage can. I cannot open those stupid bags. I can't get them started. Often I give up after awhile and get my wife to do it. Opening those tall white garbage bags is way, way harder than tucking calf heads.