I think you're a romantic.
I agree with you although I do think Denethor would do what is best for Gondor in any situation, his losing his mind aside.
"to him is
no purpose higher in the world as it now stands than
the good of Gondor; & the rule of Gondor, my lord, is mine and no other man's, unless the king should come again." [RotK, bk. 5 ch.1, p. 32]
I'm not quite sure how Denethor would feel about his son marrying a Rohirrim, although they are quite recently descended from nobles in Dol Amroth, and Éowyn's uncle did live in Gondor for a bit. I do think Denethor was a bit more old school and would not be quite taken with his son marrying someone not of high Númenórean descent. It seems he laments the decline of the High Men on Faramir's apparent deathbed, "my line too is ending, even the House of the Stewards has failed. Mean folk shall rule the last remnants of the Kings of Men." [RotK, bk. 5, ch. 4, p. 107]
Such members of the Council may include those who rode to Gondor;
"
Forlong the Fat, the Lord of Lossarnach... a man of wide shoulders and huge girth, but old and grey-beareded, yet mail-clad and black-helmed and bearing a long heavy spear. Behing him marched proudly a dusty line of men... shorter and somewhat swarthier than any men that Pippen had yet seen in Gondor... men of Ringló Vale behind the son of their lord,
Dervorin striding on foot... from the uplands of Morthond, the great Blackroot Vale, tall
Duinhir with his sons, Duilin and Derufin, and five hundred bowmen. From the Anfalas, the Longstrand far away... scantily equipped save for the household of
Golasgil their Lord...
Hirluin the Fair of the Green Hills from Pinnath Gelin... last and proudest,
Imrahil, Prince of Dol Amroth, kinsman of the Lord... behind them seven hundreds of men at arms, tall as lords, grey-eyed, dark-haired" [RotK, Bk. 5, ch1., p. 46]
Cirion did have his son with him along with the Prince of Dol Amroth and 2 Council members when he spoke with Eorl. I too was thinking of Númenor's council when I mentioned Faramir possibly being on Gondor's. In note #23 of Aldarion and Erendis it's said, "The Council was composed of members from each of the divisions of Númenor; but the King's heir when proclaimed was also a member, so that he might learn of the government of the land,".