Only the masochistic would try to do anything but plain skating, speed skating or hockey on unrockered skates. Inline slalom is done exclusively on rockered skates. Traditionally this was achieved by using smaller wheels in the end locations, but these days the frames themselves are rockered, at least for the better quality skates. But there's no functional difference in these approaches, apart from limiting your opportunities for exchanging wheels to even up wear. i.e. the point is that you can rocker ANY skate, no matter how cheap and tacky, simply by juggling wheel sizes.
Personally I do both. i.e. smaller end wheels on a pre-rockered frame. With my two middle wheels on the ground, the end wheels are flying 5-6mm up in the air. I have been told (by slalom people) that my setup is mad, but it works well for artistic type skating. The idea is that the second and third wheels are available to pivot on (with a little bit of unweighting), which means you can 3-turn in roughly the same sweet spot as on ice figure skates. Because I have a "rear sweet spot" too, I've found back 3s easier on wheels than ice.
I can even do tight loops, which surprised the heck out of me the first time it worked. You just have to get the leans right and stay on the exact middle of skate. But it feels pretty much just like it does on ice.
Yes, spinning using the ice technique seem to be not an easy thing (I can do it, but I don't get much more than 1.5 revs out of it, before I grind to a halt, though to be honest, my ice technique isn't much better), but one can certainly spin in the roller style which is essentially done on a front or rear wheel (often alternating between the two). I posted a vid in the media section, of Sofia Bogdakova doing a slalom routine features a ton of one wheel spins, and hers is certainly not the best I've ever seen. But I'm not convinced it's impossible in the ice technique, given my radical rockering, doing it essentially rolling on wheel#2 and using wheel #1 as a "rolling drag pick". I currently suck at spins on ice anyway, so I will report back when I'm there.
Yes, you can sort of do toe jumps, and you can definitely do edge jumps. I have seen axels, toes, loops and lutzes done on them. I was told that one useful technique for toe jumps is to use the whole skate placed sideways as "one big toepick". I have managed a toe loop like this, and it works, though I imagine it was rather ugly (but then again, ugly jumps are all the vogue in freeskating at the moment anyway...). Yes, you do have to land flat, but so what? So yes, if you screw it up, you can fall off the front, but you can wear kneepads, and no one will be judging you for aesthetics anyway.
So, yes it's going to be a bit different, but with a decent amount of rockering the core skating skills are totally transferrable. I go ice skating once in a blue moon, but within half an hour I get my ice feel back and I'm working on all the same stuff I left off on wheels. With all the same mistakes and fixes. But then again I don't give a rats about jumping, and only vaguely interested in spinning, I might be unusual there. I see no reason why rockered regular inline skates couldn't be used for ice-dance style dance. I intend to demonstrate this, just give me a decade or two more to get my skills up