Whether one objection against a mixed condemnation/non-prosecution order sends the whole case to the Tribunal d'accusation.
Yes. Under Arts. 271 and 272 CPP, one timely objection brings the entire case before the Tribunal d'accusation.
Where the judge convicts on part of the facts and discontinues the case for the rest, or convicts some accused and not others, an objection by one concerned person extends to the whole matter.