The CM proposal left a gap - what happens if two parties have exactly the same number of votes (rare, but will happen)? The AR decided that if two lists have the same number of votes and are most voted, there should be a second round just between those two lists. (art 135)
But the question of who would replace the mayor if they died, quit or were ousted was to be resolved in the other law, the revision of 2/97, which was not considered at the special session. The order of party lists remains fixed for the 5-year term of the assembly, but the CM draft proposes that the party or coalition most voted for municipal assembly would choose the person "best positioned" ("melhor posicionado") on the list - and "best positioned" is not defined, although elsewhere the draft makes clear it need not be head of the list. (art 59 and art 96-A of 2/97 revision proposal) This does seem to give the party the right to choose someone other than the highest person on the list.
This is unlikely to be acceptable to parliament, which would probably follow the model of article 137 of the CM draft electoral law, which was accepted by the AR. That article covers the death of a candidate during the election, and says their place is taken by the next person on this list. Probably what will be approved in October for substituting the mayor.
In News reports & clippings, 27 July 2018