Celestial pearl danios (galaxy "rasboras", even though these fish are danios) are a totally different species than pearl danios. They stay much smaller and are much more shy. Mine have always done better in a small species setup.
Definitely no on dwarf neon rainbows for a 10 gallon, and I personally wouldn't keep them in most hex tanks either. They are really active despite their somewhat small size, and I'd personally recommend tanks that are at least 30" long (although 3 foot would be even better IMO