Ideally yes,

to take exiting floor off, you can lay anything on top of anything ,people do it,

the question is ,will it last? but sometimes its not a clever idea, your flooring will be raised by hight , also the tiles could brake under the flooring , i'm not saying a high likely ,but it is possible.

the best and quickest way is, using a small kango hammer action drill, use a chisel/bolster bit and just using the hammer action setting , it should take the tiles of in no time

OK, you can, but you may run into problems with threshold levels and uneven areas. If its uneven then the floor may rock as you walk over it so if you plan on never revealing the floor again then you can put a levelling compound down to give a better base. If you don't want to do that, then you can also get self adhesive underlay which, combined with an epoxy spray adhesive, will tie the laminate down and stop any lift.

Having a ''THIN'' vinyl type flooring like Amtico or Karndean, its colud be good for getting the level for the threshold?, what about the uneven surfaces ?the whole floor will be have to be levelled off with sub flooring compound,££££££ , as explained by my colleague (Selsol Architectural,) above.

You could also lay ply boards by gluing or/and drilling and screwed to the tiles , adding adhesive could become a vibration barrier ? and could solidify the sub flooring , or become a sound barrier too ?

Yet again it could create problem for the future renovation made by you or if there is a pipe of some sort running under the sub flooring and its ''leaking'' how hard will it take to access ? i'm not saying high likely, but is possible, it does happen

the best advise i can give is take the tiles off!!