We have currently no schedule for the next enchant event because there is no regular schedule for it.
The 'I love DS' balloon can't be obtained anymore because this balloon was an exclusive to thank players who stayed with us when we had a really bad rollback back in early 2015.
Enchant success rates and soulcraft success rates are given by:
Pirate Balloon (Part of the annual Talk like a Pirate event, +4% Soulcraft/Enchant Success Rate)
Good Luck Balloon (Part of the annual St. Patrick's day event, +3% Soulcraft/Enchant Success Rate)
Rose of Virtue (Soulcraft Enchant Rate +3%)
Patch of Love (Enchant Rate +3%)
All 6 parts of the Cupid Set (Enchant Rate +1.3%)
Rose of Unity ([Event], normal and [Best]) (+3% Soulcraft/Enchant Success Rate)
All 8 parts of the Unity Set (each version) equipped (including the Rose) (+4.5% Soulcraft/Enchant Success Rate)
All 5 parts of [Event] Styling Pink Set equipped (Part of the annual Valentine's Day event, +1.5% Soulcraft/Enchant Success Rate)
All 5 parts of Styling Pink Set equipped (Valentine's Event Mixboard Set, +3% Soulcraft/Enchant Success Rate)
Leprechaun's Accessory Set (Ring, Necklace, Earrings) (Part of the annual St. Patrick's Day event, every item gives +0.5% Soulcraft/Enchant Success Rate, when wearing the whole set it gives additional +1.5% Soulcraft/Enchant Success Rate which is a total of +3%)
I might have missed something. This is what I was able to gather out of my head.