Welcome to the forums pitpit!
Have a read at this as this is a canon user planning to change to Pentax K-x:
https://www.pentaxforums.com/forums/pentax-beginners-corner-q/84447-canon-use...ip-pentax.html
Wireless multiple flash control is not an issue. It would all depend on what radio triggers you would be using.
For the lenses itself, Pentax has been making quality lenses even when Canon was still not a big name in the market.
Pentax still has the best lens on the market but it would all also depend on your budget.
As for the kit lens, Pentax has the better kit lenses offered than the other brands aside from olympus.