Did Sophy ever jack all trades? And did she even manage to defeat all bosses?
I actually just finished the playthrough yesterday after a bit of a break

In the end, I went with the following level ups after the first 7 I already outlined:
- Level 8: Fighter - Fighting style: Duelling (chose over Defence as she needed help with damage more, and over Archery as she had so many cantrips she could use at range), plus Second Wind
- Level 9: Druid - Cantrips: Shillelagh (ended up pretty pointless as didn't use staff for long) and Thorn Whip though Resistance might have been a more useful choice for some checks, also got four level 1 Druid spells
- Level 10: Rogue - Sneak attack, 1 x proficiency, 2 x expertise (I took proficiency in Deception and expertise in Perception and Persuasion)
- Level 11: Sorceror (Wild Magic) - 4 cantrips (I took damage ones - shocking grasp, fire bolt, poison spray, ray of frost), 2 level 1 spells (I took Chromatic Orb for flexible elemenatal damage, and Burning Hands which I don't think I used once)
- Level 12: Barbarian - Rage (small advantage if Sophy was going to just melee rather than mix with magic, which she didn't often), Unarmoured Defence (Con) which was useful with the amulet of health and let her ditch heavy armour and use robes that would help boost other abilities (eg Potent Robes for boost to cantrips of which she had many)
Sophy was a fun character to play, with proficiencies in six skills and expertise in four more and all the classes she had loads of dialogue options, she had 17 cantrips to play with and a decent range of lower level utility spells. Though I was playing on balanced where I was fine in most cases using fun but suboptimal choices, whereas on harder difficulties or soloing I can imagine being more limited in how far you can take advantage of the flexibility. I also struggled to find a use for a feature from every class by level 12, which I had been trying to do, though I did manage to make use of every class at some point in the adventure. Eg Monk was largely pointless by the end, as if I wanted to get any sneak attack benefit I had to use finesse melee weapons so the ability to use dex for non-finesse weapons wasn't useful, I generally had something better to do with a bonus action than a puny unarmed strike, and the barbarian unarmoured defence trumped the monk one once I had the amulet of health from the House of Hope. That said, those monk features were handy earlier in the adventure.
It was also fun from an RP perspective to play a character who was endlessly curious. would take silly risks, say yes to almost anything, and always want to poke her nose into any business. And though that didn't end well for her, at least the transformation she went through at the end gave her a boost to some stats that came in handy in the end game given she didn't get any ASIs.
All in all, would definitely recommend JoaT as a fun challenge to try, though wouldn't for a moment claim I managed to do it the best possible way!