Was Dassault personally involved in the design of Ouragan, Mystere and early Mirage or by this point he was having more of an organizational role?
He was involved : deeply.
If you look closely at the Mirage IV-01 in June 1959 and the Mirage 2000-01 early flights in 1978, you'll notice the vertical fin is different - taller and
uglier. Well in both cases Dassault asked his engineers to change it - and they complied.
One could say he was a micromanaging A-hole bureaucratic boss, but that's not the case.
For a start he was an aerospace engineer himself, harcking back to 1916 and its early successes. Almost importantly however he respected his engineers and pilots opinions if they were right - even if he disagreed. He had flair, but he also had another flair - to accept being proven wrong.
As for briberies - he was a MP for the Oise departement, and he cautiously courted both sides of the political fence : Mitterrand (the left) and Chirac (the right). It served him well during the 1980's.
But Dassault success over the state-owned companies (tacitally acknowledged by De Gaulle and his 1960-69 minister of defense Pierre Messmer) mostly relates to their flair in navigating the Armée de l'Air gold-plated, blue-sky RFPs : fiches programmes, as we call them in french. Think of AST.396 or OR.339 - the AdA had their own.
Dassault developped their own method of survival.
They would built top-of-the-list prototypes according to the RFP - knowing perfectly the said planes production would be totally unaffordable.
In the meantime, they would develop a cheap "Plan B": building a single prototype mostly on their own dime (because not matching the RFP) - thanks to massive export orders starting with India deal for MD-450 Ouragans, in 1953.
Once the AdA realized the RFP plane was too expensive, Dassault would propose their own "Plan B" instead - and carry the day.
Cases in points:
-Mirage III : born out of the AdA and NATO, 1953-1958 LWF fiascos; and the related Mirage I & II failed fighters;
-Mirage F1: the most spectacular example.
Born out of three massive RFP failures and their related prototypes: VSTOL, VG-wing, and a few additional F- Mirages with swept wings. The list : Balzac, III-V / F2 & F3 / AFVG - Mirage G - G4 - G8. Whew.
-Mirage 2000: here we go again: F1M53, ACF plus Mirage 4000.