Every time I have a conversation on the phone with a customer, and i give them our website or email address I wish my boss had picked a name that people can spell easily. I have no idea how many customers are lost because they send emails that never reach us.
So based on that, let's look at your list!
Reign of Colour - people won't be able to spell 'reign'
Reign of Ink - as #1
Raining Ink - possible
Ink Warfare - possible
Colour Warfare - possible
Inkspire - easy to misspell
Vivid Pixel - possible
Inkspiration - easy to misspell
Colour Asylum - people won't be able to spell 'asylum'