My first character was "Brianna Foerider", a doe-eyed necromancer with lavender hair, not the stereotypical vamp. I missed a number of quests but somehow made L10, I guess with some extended grinding near the end. As I played through on the later characters I realized "hey, I didn't do this with my first character", so when I was about done with character #4 I went back to Brianna to do the quests I hadn't done with her, and discovered quests I hadn't done with the other 3... So, I think it's entirely possible to reach L10 with a minimum of grinding for XP, and maybe even L11 if you sniff out and finish every quest possible in the free areas.
You start with a dorm room comparable to FFXI's "Mog house", which you can decorate with furniture items and stash unused gear, pets, mounts, etc. Unlike FFXI, there is an extensive custom-castle estate system. While I was tracking down quests I'd missed on Brianna, a high-lever player "Alex" invited me to look at his. He said it was his design, not a stock floor plan. That part of the game is maybe more comparable to Yoville or Second Life. If it costs around $60 to unlock all areas without being a subscriber, Alex's playboy wizard mansion probably cost hundreds, maybe thousands of dollars.
My other characters, in order:
"Cheyenne Shadowpyre", Balance mage (elementalist)
"Calamity Skullgiver" (yes! lol), Life mage (healing/nature)
"Morgan Mythwhisper", Myth mage
Schools I didn't play characters through: storm, ice, and fire. All schools follow the schtick of summoning iconic creatures to inflict damage. Aside from some wand-supplied "zero level" spells, you can't just cast a lightning bolt (Storm) or life-drain (Necro) or make a magic-powered weapon attack (various) - you have to summon a proxy storm snake which maked the lightning zap, a ghoul to do the life-drain and turn around and channel the hit points back to your health meter, or a trio of ninja pigs to do their leap-kick thing. So there are a menagerie of low-level dark and light pixies, fire cats, storm snakes and beetles, and then at higher levels you get the iconic summons: snowman (Ice school), phoenix (Fire), vampire (Necro), kraken (Storm). The Balance and Myth schools are kind of throw-aways, evidently worked in to complete patterns of relationships between other schools. So in elemental magic you fire, ice, and storm mediated by Balance, and then in non-elemental you have life, death and ... something, maybe myth, mediated by astral, or maybe life-death-astral mediated by myth.
Presumably the quests that leave you hanging, starting in the free areas but directing you into non-free content, would continue the leveling pace. Brianna actually made L11 with xp from tracking down unfinished quests. Pets, PvP, and crafting are all unlocked by L10, and you get your first third-tier damage spell at L10 too, so PvP might not be too boring. L12 would be when you could move out of the dorms into your own castle-estate, but I doubt there's far you could go with that, without plunking down token "crowns" purchased with real cash. L12 is also when you get the option of buying back spent skill points, to reconfigure your character customization.
There are references to an 8th "Astral" school in the spell-deck UI, I never figured out what that was about though. Also, PvP offers a couple spells like Stun, in exchange for skill points. As a free-player I figured it was pointless to challenge paying players even at low level, so I didn't toy with that. I did see one person use Stun in battle, out of all the combat joins I experienced. Maybe the PvP spells are the astral school.
Speaking of combat joins... this is a mixed blessing. In the earliest encounter zone, Unicorn Way, there are these purple "boss" dark faeries that seem to spawn uncommonly among the regular red "elite" corrupted faeries. I was very curious if the purple ones had some special loot drop rate, but INVARIABLY as soon as I tagged one, other players POUNCED to join me. I didn't need help; I really just wanted them to fuck off and let me soro these nominal "boss" faeries. In FFXI it was a design feature that you had an exclusive lock on a monster as soon as you engaged it, and the only way someone else could join was if you were linked up in a party. In Wizard101 there is no solo mechanic - every battle is open, up to 4 players, and if there's a monster roaming in the area then it will join to even up the match. The bit that breaks the fourth wall is that if you tag a monster and no one else joins, then no more monsters will attack you for the duration of that fight. You can walk into a group of monsters, one will lock on and face-off in the battle circle and the rest will despawn. Very ritualized and not at all realistic.
This is somewhat handy when you're grinding for XP, because XP is mainly a function of total spell-points worth of spells cast, player and monster alike. So there's a synergy effect when you get a group of 4 people all drawing out a battle to maximize XP... as long as they're all light on their feet, selecting spells quickly, rather than taking the full 30 seconds per turn to select a spell for that turn.
It becomes an annoyance when you want to just kill quick and move on, and people make you wait. That was part of my irritation with my dark-faerie joiners, and later in the "kill 5 of this kind of monster" quest segments. I wanted quick kills to assess loot drop rates, or put a quest behind me, but ended up having to wait through an extra few minutes per fight because their joining drew in corresponding monsters. And apparently they thought they were XPing, so they dawdled over tactical spells, and got a little stiff when I one-shotted their assigned monsters. Some control-freakies had the nerve to join my battle, and then tell me "pass", "don't kill", "I can do more damage than you". I don't care if you can do all the damage ever, plus five; I didn't ask for help and I'm not accustomed to taking orders from strangers who decide they should be in charge of my gaming experience. Unfortunately the filtered chat does not allow the word "freak". I was constrained to express myself only with the word "controlling".
I might do one more character, just to see if males get the same kind and amount of unwanted attention. That's not specifically a Wizard101 thing (although I will pick a school I haven't played yet), more of a study in gender relations. I think it also has to do with the much lower age (and hence maturity) of the Wizard101 player base.