✔ 最佳答案
Rare Candy levels you up exactly as if you levelled up by battle, which means if the pokemon is EV trained, then it will gain bonus points from that. However if the pokemon is not fully EV trained then it will miss out on bonus points because it's not gaining any more EV points during the time it is being Rare Candy'd up to 100. Using Rare Candy to go from Lv1 to 100 misses out on all 127 bonus points.
Yes, the Effort Ribbon can only be obtained by a pokemon with max EVs. So if the pokemon acquires the Effort Ribbon, then it's 'safe' to Rare Candy it up to 100.