They look like azaleas to me, although the bottom picture shows some stressed azaleas. Could be for a number of reasons. Do they get the same amount of sunlight and water as the other ones? (E.g. both get morning sun and afternoon shade, etc.)

I have a free azalea I got off Craigslist from a lady; it was getting fried in the sun in her yard. It looked like your bottom picture, but is improving a little now that it is in shade with mulch to keep a more consistent moisture for its roots. Ironically, she cut the other azalea she had down to a stump, and it sprung back with the most beautiful growth and is now one of the best plants in front of her townhomes. Go figure.

The top ones are on the south side of my home and get more sun than the bottom ones as they are on the west side and get only evening sun. I think I remember the bottom one always doing well though so I was unsure of why it would start to look bad. Maybe I should do the same as her if they don't improve in the next couple of months?