So there's a grand total of 1475 stars to be won from the quest line + daily log-ins.
Now, assuming Inno is generous and gives us say, 30 stars to start with, that's 1500 stars = 150 matches.
Each tree needs 20 candles to lit, with each match lighting between 1-3 each.
You'll get 3 upgrade kits from finishing the entire quest line, thus leaving 8 needing to be acquired through lighting up trees for the grand prizes.
To get all 8 additional upgrades, requires lighting up 15 trees x20 candles = 300 total candles.
Thus, without diamonds, and without winning any additional stars through things like the Shuffle tile, etc..., you'll have to average exactly 2 candles per match to win a full Lv12 building!
So basically, outside of the 'RNG blessed', most people will be forced to spend diamonds if one wants a fully maxed out Lv12 building.
So much for the Xmas spirit Inno...
Between likely ending up at least 1-2 upgrades short, even *if* one completes the entire quest line + daily log-ins, AND, all the gakking forced C-map progress, this event a steaming pile of poo-smothered coal.