Needing help with some corals, please

[jsmithphoto1]

Hello all! I just have some questions as I am just starting a nano 5 gallon reef tank. The last reef tank I had was about 5 or 6 years ago and it was a 75 gallon with 500w of 20K metal halide lighting. So, this nano tank is uncharted territory for me! LOL! I am adding some photos to help describe what I am dealing with, but it's a bow front tank so please don't hate me if they are a little distorted.

First, there is a coral I purchased that I just love, but I have no idea what it is. The polyps are very small and they are blue "buds" on somewhat of a tan "stem". They kind of resemble a Xenia, but much, much smaller. In fact, this colony is on a snail shell if that helps.
TOP LEFT PHOTO

Secondly, I purchased a Pulsating Xenia that was thriving in the LFS's tank, but with mine it just kind of shut down. The man at the fish store told me that it may take up to a week for it to open up, but it has been the same for several days now (almost a week). I admit, when I brought it home, I started with a fresh tank of water. The only live thing in it was the arag-alive sand and the pouch of bacteria that it came with to help the sediment settle. Also, It was several days before I put food in the tank for it. My job sends me out of state and I was gone for 5 days before I had the chance to feed it. When I got home, the very next day I purchased some MicroVert and put some in a dropper and squirt some on it directly. Since, I have put more MicroVert in the tank for it and my other corals. Needless to say it has shriveled up with white whatever on the buds. Some are open, just not vibrant and thriving like they were. Is this specimen dying or just recovering?
TOP RIGHT PHOTO-sorry for the distortion!

Thirdly, I purchased a Blue Mushroom coral and it was attached to a display rack. The guy at the fish store had to cut it off, which is okay, and on the way home I was like "I'll just get some gel super glue and glue it to some rock." Well, I've done that about 3 times and it still manages to come off. And, when it comes of and I turn it to what I think is right-side-up, it flips itself over. I'm sure it knows what it's doing, but my question is, can I just rubber-band it to the rock or should I just leave it be?
BOTTOM PHOTO

Thanks so much for y'alls help!

[jsmithphoto1]

Any way other than URL to add photos?

[Sniperhank]

Pretty hardy corals. The blue snowflake is a xenia, just not the same type as the other xenia you have.
You can't glue a mushroom in place. They can let themselves go and travel to a spot where they are happy. If it isn't happy, it will do this and end up in a low/no flow spot in your tank.