Cory - people are just saying their honest feelings. Many things make up an image - exposure, composition, subject matter and finally, presentation. Yes, presentation. As a photographer, I can wholly understand your wanting to protect your images and make sure that people don't rip them off - let's just say if someone was really desperate, they'd clone out the watermark (it isn't that hard to do). We both know that that just adds to the copyright violation, but there are people out there that sadly do so.
I've had one of my images used on a website, and it was, as per my request, accredited to me as the copyright owner. This was an Australian birding website that helped me ID a bird. I told them it was OK, especially since it was a uncommon to rare bird, and he didn't have any image of this bird on his site. I'm happy, he's happy. In the end, as a photographer, you have to make some decisions on helping others out who help you and allowing them to use your images (usually gratis).
My personal thoughts are that I don't have any issues with a educational institution wanting to use my images gratis - but they must first ask me for my permission, secondly attribute copyright to me, thirdly, give a link to my website, and last - not sell it for profit. If some of my images help children (or adults) learn more about Insects & Arachnids, then I've done my bit for nature. Of course, I'd love to sell some of my images, but then, I have to be *good* enough to warrant customers buying them.
Anyways, that diatribe out of the way...
#1 - it's a tough call this one. Why not consider taking the shot at smaller magnifications, giving yourself more DOF, and cropping? This will depend on the camera of course, and how much MP you have to play with. It's an ugly hack, but it does work.
#2 - Ah OK, it's probably just the resizing for web that makes it look like that. Not a biggie.
#3 - Sounds good to me.
#4 - It's hard to say, one man's gold, is another mans fools gold.
#5 - Sorry! I'm particularly hard on myself as a critic, and sometimes I do that to others. I don't mean offense, just offering my honest advice.
#6 - Same as point 5!
In the end, these are just my thoughts. They are not set in concrete. Just thoughts and suggestions. That's the beauty of these forums - so many talented photographers, and most of them are always willing to try and help you. I'd be doing you a grave disservice if I didn't return the favours that others on this forum (LordV, Bald Eagle, Hatch 1927 and so forth, too many to name, apologies to any that I left out) have given me by helping me out when I was a newb.
Dave