Yes, there are default ghosts. That's what "0G Ghosts" means. They're selected by default when you enter Ghost Battle... you actually need to touch a button to NOT race against the default ghosts. When someone races a 0G ghost and uploads the data, it becomes a 1G ghost... when someone beats that and uploads the data, it's a 2G ghost, and so on.
There doesn't appear to be any way to save ghost data that I know of...you just download it, race it, upload if desired and if you win... and then you start all over. I don't think it's a question of locks on ghost file saves...I'm thinking that there aren't ghost files saved at all (except for your own that can be saved manually).
I don't think there are options for AI difficulty, etc. Then again, there really isn't much reason to race the AI. Compared to online races and ghost battle, Spot Races are pretty boring IMO...it's pretty much the equivalent of the Arcade mode in RR PSP/6/7, which is to say...it's pointless.
The framerate is most definitely 30, at most, not 60. I wish it was 60.
My feelings on the whole team system...
I wish there were weekly team rankings, and that the CR you get for free each day would be based on those. It would give me more incentive to actually give a crap about the whole team business. As it is, tens of thousands of points separate the teams, and I feel like the 5-10 VP points I typically earn per day aren't going to make much of a difference.
It really seems like these companies don't take pages out of each others' books. DJMAX Technika 2 did well with the whole Crew Race system and Technika 3 refined it further. Every game played adds EXP to whatever Crew the player is a member of... if the Crew makes the top 90 for the week, they are ranked, and every member of that Crew earns bonus Max Points in a particular game mode for the entire following week (plus a substantial free bonus before the first game played that week). There are overall lifetime rankings too, but they don't have any bearing on bonuses...only the weekly ranking does. Something like that in RR would have made it feel a lot more motivating and competitive, versus this whole "2 points if you race against these teams, 1 point otherwise, and these rankings will never change" thing.
The other day, I booted up RR and it acted like I was starting for the first time...it asked me to select a team all over again. I freaked out, powered off, powered on again, started RR a second time and all was well. But I noticed something when the "select a team" screen had come up: it was offering me a 100 CR signing bonus for the Trianchor team. Yeah, the team that's in first by a few miles. Why is the game not offering signing bonuses for the 4th-place Squaris GP? Is there no balancing going on here?
Also, I'm spotlight VIP for the fourth day running. This hardly seems random, heh.