I know when ever me and my dad install a slide we have to wait untill the concrete cures anyways before we can install the slide so i dont think youll have a problem with cracking the concrete.
I dont know which slide your looking at,but the ones we install,we just use a hammer drill to drill holes into the concrete and tap the locking anchor in,and the slide the slide over the holes on put the bolts in,thats all we do as far as bonding.
As far as liabilities,its the same whether you installed it right when the pool was completed or like what your wanting to now, a couple years later.I know in some cases the the home owners insurance went up b/c they installed a slide but ever case is diffrent.I know whenever we install one the manufacturer incourages us to have a million dollar liability coverage just in case somthing happens.but dispite tht risk we do install quite a few.
There really not bad to install,again it depends on what brand you get otheres are simpler then others.the type we use it takes us a half day to a full day to install it properly and we know what were doing.I say for somebody doing it on thee own with our type of slide its a good weekend project,its not bad.
Heres the type of slide we install.
http://www.youtube.com/watch?v=2lHfFJAHyHY
This slide is quick,and they say nobody under i belive it was under the age of 12 or so many pounds i cant remeber should be on it,but ofcourse little kids use it any ways.As long as your responsible with it youll be fine.We like this slide b/c of the high sides and it has handles on the ladder part so it makes it easier to climb up.let me know if you have any more questions ill be glad to help!