A lot of people may disagree with this, but in theory Don Jr should be the last person indicted in the investigation and the final report that includes Obstruction of Justice should be released to Congress at the same time.
You’re absolutely right but only under the assumption that the investigation is not in danger of being stopped. You strangle off his lifeblood by moving closer and closer to him through his associates. When the report is in its final stages they will pick up any current members of Congress, then his family starting with Kushner, Ivanka, Eric then once the the report hits.....Don Jr.. Let him keep jumping offsides and adding more obstruction.
You have to tell the story as you indict/arrest while leaving out any information that exposes anyone too close him until it’s too late and the report is released. Otherwise, he’s going to do something stupid and you gotta hit the deadman’s switch and reveal everything all at once...... which is a disservice to all the work they’ve done.