Okay, I'm going to try this again!
Don't worry, I've run into problems, too, when I've made posts. My sleep deprivation even had me mistype information a little earlier.
I agree with your plan . I would also establish an alliance with the dwarves as soon as I could. The mages will need a reliable source of lyrium, and it would prevent the templars from getting that advantage.
That would be a good idea, as the Chantry may have lost control of the lyrium trade on the surface, and the mages would require lyrium for their magical feats. The land of the Dales actually borders the Frostback Mountains where the entrance to Orzammar is.
Which Fereldan ruler do you think would better serve our purpose- Alistair, Anora or both?
My canon Surana Warden convinced Queen Anora and a personality hardened King Alistair to marry. Given the crisis with the Breach, I think they could both be convinced to throw their support for the Inquisition, as well as a possible treaty with the Dales (perhaps through Josephine). When it comes to the mages, both rulers will want to respect the ultimate sacrifice of the Hero of Ferelden by giving the Circle it's autonomy, while both will publicly proclaim that the mages have earned the right to govern themselves if the Hero of Ferelden asks for his people to be free. King Alistair is still arguing about mage autonomy several years later when the Champion of Kirkwall encounters him with Meredith.
As for the elves, both rulers also show an interest in helping the elves, although Anora's attempt fails (which leads to a crackdown on the elves in the Alienage) while Alistair's move is progressive enough to prevent an elven rebellion (because he places an elf at the royal council to give them a voice, in spite of all the controversy it causes among the humans). I also think both would have valid concerns about Orlais, and could see the potential use in having an ally who has a mutual concern about the imperialistic tendencies of the Orlesian Empire.
Perhaps the Inquisitor may be able to take further steps in making certain that Orlais doesn't pose a threat to either Ferelden or an independent elven kingdom of the Dales.