Soon, the ultimate Sony failsafe word
"Home will be back online.....Soon™"
Come check out my Twitch TV channel, will be streaming various PS4 games from time to time http://www.twitch.tv/reddaxel
Won't those colors run out when your PLUS runs out?
Yes, it will probably reset you to the default blue the next time you sign into Home. I would assume something similar would happen to your avatars that use custom colors for hair and makeup.
There are also additional avatar save slots for Plus members, and my guess is that they will simply be greyed out and inaccessible until you renew your subscription.