You can reimport as many times as you want (well, you know, within reason *g*). I don't know whether it will necessarily fix the "wrong icons" thing, though I remember someone mentioning it so I'll see if I can find out for you. But repeated imports just pick up anything that's changed since last time, so it'll get your new posts or anything it missed before. Also, there is a crossposter being worked on that will allow you to post to more than one journalling site right from DW itself.

Icons - if you import all your icons now and then revert to unpaid at open beta (or afterwards), I'm pretty sure it'll drop you down to the unpaid icon limit. The unused icons will be there on the server if you renew your account, at least in the short term. I think that's the same as LJ, really.