Well, you can use a clicker and some hot dog, and get him orienting strongly towards whoever says a certain word... that certain word being his new name, in probably 3 15 minute or less sessions. So don't worry about being stuck with something that sounds like Mischief...
I am totally computer illiterate! I was able to use blogger to make a little page about an adoptable dog. You can make one, and then use that link in other bios, like on PetHarbor if merriterrier will let you use her account there. Just put in the link and say, "Link to more info, pictures, and video here!" Seriously, the blogger site was super easy to use. Like, I use a 2002 Nokia phone with no camera or graphics capabilities, and I was able to do it.
It lets you put video links and pictures on there along with text and the pre-made backgrounds and set-ups are all pretty palatable if not outright appealing.
The picture on the link you posted, he looks totally different! He has a cute little face and I would definitely show that off. I often will pose Booker in a sit-stay or down-stay and take pictures that way. I taught him to "look" and after a few shots then I go in and reward him in place... it helps work on his stay command and also lets me get all the photos I always used to post of him...
If he doesn't have a reliable "stay" then I'd just tie up his leash to a tree on a sunny day, and step back a foot or two. He'll be in the shade but the light will be good. Lie down in the grass and snap some photos. Roll him a ball and take some of him being cute chewing the toy, at dog-level.
What activities do you do with him now? Can you record any of them? Video is really helpful.
If he's housebroken and rings a bell to go out, but if nobody responds he'll go in the house, then I'd say "I ring a bell to let you know I need to go out to the bathroom" or something positive like that. If he's totally nonconfrontational with dogs and doesn't even spark up when a dog goes after him, that's pretty impressive, and I'd say "I was adopted to a home with a older dog who bullied me around too much. I still really like friendly dogs! I would like to [play tug/slam and wrestle/play chasee and chaser/whatever his style is] with your well-matched, friendly dog!"
In what ways does he act like a Lab? You could say, "Thanks to my Lab heritage, I love to swim! I'd be a happy, brave companion on camping and fishing trips!" or "Yep, I'm mostly Labrador, which means I LOVE to play fetch! Do you have a Chuck-It and a supply of tennis balls? I'm your guy!" rather than, "I'm mostly Lab! I bark a lot and shed like crazy and tend to put on weight easily!" hah hah.
As far as being afraid of men... does he just duck? Growl? Bark? What does he do when pushed? Can you continue to do work on that (which would make him more adoptable) by having lots of men either toss him treats or toys and not rush into any physical contact? "I used to be a little timid around men, but I've come a long way using treats and my favorite tug toy! I've never growled or nipped at anyone while with my foster family. If you give me ninety seconds and my favorite snacks I recover quickly and will be everyone's new best friend!" or whatever is true here.
Is he able to relax in the house? Is he destructive? Does he pace? Alarm bark? "I do a good job of barking when someone is at the door, but as soon as I know they're friends, I'm all wiggly!" or "When I hear people outside my front door or noises-- I never bark, I just start drooling, because it might be pizza delivery!" "I'm a high energy guy outside of the house and can go for long hikes with you! But on busy weekdays if I get to play some fetch and go for a walk, this works for me, and I will curl up and snuggle next to you for hours!" or "I need lots of exercise! A doggy treadmill helps me on the days we can't go for bike rides. Making sure I can run for 30 minutes twice a day helps keep me from developing naughty habits" etc
"I'm already crate trained! I sleep in crate quietly when my foster mom is at work. At night time, I sleep on my own dog bed, which will come with me to your house!" or whatever
"I'm mostly Labrador, which of course means that I LOVE food! This means that training can be easy. My foster mom has already taught me _____________. Here's a video of me showing off my skills!"
Stuff like that. "I am very good for getting my nails trimmed and my ears cleaned! Plus the vet said I was a star at the clinic," or "I am learning to accept my pedicures; my foster mom will show you how far we've come! I'm scared of needles so the vet is not my favorite place, but ever since we started dropping by for a quick visit and a treat, I'm starting to realize the staff might not want to eat me."
These give an honest idea of the dog's personality, and can be kept reasonably brief. Nobody wants to read 5 paragraphs about a potential foster. They look at the pictures, find a cute dog, read the description, and halfheartedly look for serious incompatibilities.
That's depressing about adoptapet. Don't feel too badly he's only been viewed by you, it isn't a big system. If MT can get him onto petharbor, that will help, I think. Also, is there a lab rescue there that would be willing to cross-post him and a link to his new awesome bio when it's done? I mean, I would be willing to help you with the blogger part of it, I just can't guarantee it will be done in the next 3 days or anything, but if you can get some new pictures/vid/descriptions of him I can probably get it onto blogger and looking cute. Then you can facebook/e-mail/twitter the heck out of it.