The whole process of blossoming + maxing to Lv.80 makes it more costly than evolution, so my personal preference is that gacha units always take priority. Primrose gets an additional x1.2 skill activation for her party, so hers will be more beneficial imo.
Stat increase in bloomed state is noticeably slower than in evolution state, so it'll take quite a while to approach the stats of Lv.70 pre-bloom. That's where the usefulness of the heart and affection stat bonuses from blossomed gifts comes in for girls with blossoming.
Re-reprinted (permanent) events are being added on a monthly basis, usually on the last maintenance day (Monday) of the month. Based on where we're at now (permanent #16), the ETA for Lily of the Valley Tree is 3 months; Amazon Lily is 26 months.
Welcome to the Orient. English names will work fine. I'm sure some of the Japanese are using Romanized names.
If you need some more allies, here's my ID: 112112066. I'm level 144. Let me know on this thread if you requested me.