#1&2 are either Aulonocara Stuartgranti "Maleri" or Aulonocara Baenschi "Benga"...I don't know how to tell them apart and neither do the knowledgeable people I've talked to, but unless you know where they came from or you bought them from a good source who knows exactly what they are, then you can be sure of what they are. I'd just stick with calling them "Sunshine Peacocks".
#3 Aulonocara Sp. "Fire Fish" ... these are hybrids and have a few different other names
#4 I'd say your right in saying its a protomelas sp. "taiwan reef"
#5 Leporinus fasciatus?