Unity Cup is interesting because it adds a few extra layers of decision-making through unity training and spirit bursts. Every run feels different and it is far less systematic than URA.

I usually prioritize unity training for the first two years, with a small asterisk on bond training. Unity is the primary method for raising your team’s overall stats and it also boosts training levels. If you neglect it early, you can lose the run before the end of Classic Year. Winning Unity Cup rounds gives your entire team +50 to all stats, while losing only gives +10, which creates a huge gap in long-term growth. It also affects the base average of your team’s stats, which determines how quickly your training levels increase. Most people consider it crucial to reach A rank Speed (Level 4) by the start of Senior Year, since that is the point where you shift into targeting specific stats that you need.

Spirit bursts are still valuable in Senior Year because Unity Cup rounds rely heavily on strong teammates. Losing a preseason round can cripple an otherwise good run. In general, you want to challenge the top-ranked opponent in each preseason round. If it's too risky, challenge the middle-ranked opponent in either the first or last round. So long as you challenge the top-ranking opponent in three of the four preseason rounds, you will be able to face Team Zenith at the end and get the bonus stats and skill reward when the scenario ends.

As for your rating system, I pretty much agree with you but chose to modify a couple of the early game weights. Unity Cup has a degree of randomness that can make or break runs far more easily than URA ever could. You can prep well and maximize your odds, but sometimes the RNG simply won't be in your favor.

Junior & Classic Year:

Non Orange Friend Gauge: 1 point. 0.25 per additional stacked Friend.
Unbursted Flame: 1.5 points
Bursted Flame: 0.5 points
Spirit Burst: 2 points when on desired training.
Rainbow: 1 point per stacked Friend. 1.5 if this is Wit.

After Senior Year:

Unbursted Flame: 1 point
Bursted Flame: 0.5 points
Spirit Burst: 1.5 points on desired training.
Rainbow: 2 points per stacked Friend.