Hey! I'm not well-versed in UKC, but I have had all three of my girls show once in that venue though, with Scarlet being the latest.
So, UKC has no grooming products on your dog, which is fine. Just have a clean, blown-out dog with his toenails appropriately short. Not Dobe short!
I use a silver colored fursaver, and a 6' thin (1/4") leather lead.
As for his ring behavior, you don't want your dog to shy away from the judge. You want the judge to be able to go over your dog, and able to check to see if all his teeth are there. He doesn't have to behave like he's done this this whole life, when you are first starting out, but he does need to be moderately well-behaved. Most judges are fairly friendly, and are pretty forgiving of puppy (or young dog) shenanigans. I don't pretend to know what goes on in some of the judges heads about why they pick who they pick, so I don't know what to tell you about presentation vs conformation. Your boy looks very nice. I don't know why he wouldn't do well.
No written critique, and you probably won't get any feedback in the ring. Where ever you are placed in the class, if you get a ribbon, thank the judge when they hand it to you. If you want to find out what they thought about your dog, you can find them when they aren't judging, and not busy, and ask them.
Just look presentable. I've seen pants, jeans, skirts. Shoes that you can jog around the ring in (though the rings I've seen in UKC are pretty small, so it's not going to be an all out gallop like in AKC)
I donít know if UKC allows the use of bait.