That is not correct in my opinion. Your sentence puts the emphasis on "him", meaning: we have soup for everyone but not for him... The original sentence means: we have no soup that he would like.
That is a wrong question. Most Czech words can either be stressed or not. Obligatory clitics can only be unstressed and some pronouns either behacve like clitics or can appear in the strong position. See the Tips and notes for the obligatory clitics.