If you wanted to be able to pump out as many scrolls as possible, with the widest variety, what would be the best options to do so? And once you have them, who is the best at using them?
A 17th level Medium can get access to 9th level Wizard spells once per day, or 8th level Cleric spells and 7th level spells from any other list (via Miracle) once per day, so I imagine they're hard to beat on variety. They don't really have anything built into the class for scroll creation or use though, as far as I've seen. Plus, 17th level is pretty late to be getting access to a single higher-than-6th level spell per day.
Spell Sage Wizard can get access to Cleric/Bard/Druid spells of whatever level they have at least 2 prepared spells of, but they give up their Arcane School to do it. No access to Psychic spells though.
Rebirth Discipline Psychics can get up to 8th level spells from any list, but only once per day.
The Pathfinder Savant prestige class and the Razmiran Priest Sorcerer are both good at using scrolls, but don't quite have the range for variety, or special abilities for crafting.
Spontaneous casters could use Mnemonic Vestments to essentially make copies of scrolls they already have without using up the original.
Are there any other ways to cast from a scroll without using it up?
Well, to be honest there isn't a lot of archetypes that focus on scrolls. Wizard has the Scrollmaster...who gets some silly abilities but at 10th level they get the good one that says they cast spells from scrolls with their own int mod and can use their own CL.
For creating scrolls, its just traits, feats and supporting NPCs. Other than Scribe Scroll, cooperative crafting would be extremely useful. Any assistant with both feats would effectively let you add another 1,000gp to your base amount per day, doubled if you rush crafting. They don't even need to know the spell you are inscribing. I don't believe such assistants actually perform the aid action to boost your skill.
Hedge Wizard trait will let you craft for 5% cheaper. Not much help there.
Leadership can be the most effective feat for crafting. Especially if the GM allows you to use Downtime Rules. First thing, establish a base for yourself. Make sure it operates in such a way that you generate Magic resources with it. Then pay for Leadership. Your initial cohort can be any class (so you can boost your access to spells this way), but you need to make sure as they level they gain the feats you need for crafting. Also talk to the GM and make sure any 3rd level or higher followers you qualify for have both scribe scroll and cooperative crafting. Having an established base where you create scrolls should go a long way towards convincing the GM to allow you to get more or less what you want. Especially if you use Downtime Rules to hire Teams of Acolytes and Mages to create more Magic Resources for you, and you define each team personnel to be one of your followers. Even without leadership just talk to the GM when you hire a new Team and ask him about offering extra to hire talent with the appropriate feats.
This way when you are off adventuring the Teams can generate chump change, and Magic Resources. The Magic Resources will basically halve your crafting costs. And when you are ready to craft the teams can spend the day assisting you (earning no income) and make for one massive scroll. You might even be able to use the 1st level followers to aid your skill check to create the scroll.
Oh, and one massive benefit to using followers for the teams and organizations is that you'll never have loyalty problems if you disappear for an extended amount of time. Loyalty is an issue if you leave a team or building for more than 2 weeks without visiting to manage it. Hiring a manager helps to alleviate that possibility.
Also if you have a familiar it gains your feats. So effectively you could use it to cooperatively craft. This does give you a -2 penalty to leadership, so if you are going that route it might be a bad idea.
The biggest problem I know of (and don't know if there is a way around) is that you are only allowed to make one magical item per day. Meaning that you can make at most 1 scroll per day. Now the GP value that you can create can be increased in some various ways (base value of 1000 gp) but once you finish the scroll, that's it.
I don't think the Legendary Hierophant ability will work with scrolls. Unlike the Legendary Archmage, which grants you the ability to cast a spell, Legendary Hierophant lets you ask for a miracle (not cast the spell) and while that miracle works like the miracle spell in a lot of ways, it is also different (you can't provide diamond components for more powerful effects)
Beyond that, while miracle can duplicate the effects of a other spells, doing so also is not casting those spells. You can't use that you have prepared Miracle to create a scroll of raise dead, even though miracle could produce the effect of raise dead.
Also while Rebirth Pyschics can indeed get up to 8th level spells from any list, once per day, they are limited to one particular list per level. So you couldn't get wizard spells one day and cleric spells the next unless you gained a level right then.