Could not fit in a comment...
To my understanding, paralogs and orthologs refers, as you said, to the relative isolation of gene copy to the isolation of populations (and eventually species).
Gene conservation on the other hand refers to the variability of a given gene along many species. If a gene does not show any variance along many species, than we say that it is a conserved gene.
Eventually, gene duplication may allow for neo-functionalisation, sub-functionalisation or loss yielding to variance among this gene copy. Aside the philosophical problem of what is the identity of the gene, there is no relationships between the concepts of orthologs versus paralogs and gene duplication.