Ooh, fun. Different to see a dovah with forelegs. Remarkably it hadn't sunk in that they are wyverns until I was able to play as one and got a proper look at myself.

If it helps, the names are usually three distinct words, e.g. mir-mul-nir is valid, frin-ros-ahmul isn't because ahmul is a compound word so it's actually four words. Compound words can apparently count as two, e.g. rel-onikiiv is canon, but is probably really rel-onik-iiv or something with a word we don't know.
However the dov can also take nicknames when working with mortals that don't map to the usual rules.
UESP has more on this on the dragon language page if you're serious about getting the name to match canon.

Having been down this road recently and done a ton of research in the dov, here's some more pointers in case they're useful - if not, or if they're just "Skyrim inspired", just ignore me. For the background, consider where he came from, what his attitude is towards mortals, and what his attitude is towards Alduin.
First is important because unless Akatosh created a new dragon from scratch, he's either a survivor who's been hiding out somewhere, or one of Alduin's resurrected. It looks like Alduin can only revive buried dragons, and dragon burials stopped early in the First Era so the likes of Mirmulnir and Vulthuryol must have survived the purges because if they died later they likely wouldn't have had their bones preserved, and Mirmulnir was certainly alive in the Second Era as per "Atlas of Dragons".
When Alduin resurrects a dovah his first words are e.g. "Nahagliiv, your soul is mine for eternity", so anyone he revives is press-ganged into doing his bidding, though it doesn't appear to be a compulsion as Odahviing at least was able to betray him and others were clearly having doubts too. In the case of my other guy, Sweet-Roll-Devour, Alduin got the wrong name anyway, thinking he was a more useful dragon.
So. Attitude to Alduin - either you're one of his goons, one of the dragons fighting him (Paarthurnax obviously but there were others), or potentially a neutral dragon who is just staying out of it. The neutral option may also mean that they're quietly concerned about Alduin but don't think they can do anything to stop him.
Attitude to Mortals - again, there were several dragons who sided with mortals in the Dragon War, there were also a number of dragons in the Second Era who pledged to serve the Empire in exchange for not being slaughtered, however most of those do seem to have died anyway, one way or another. If you're one of those it's likely you would have gone into hiding anyway since although there's at least one in Daggerfall, no dragons are shown after that in the Third Era.
You could potentially be anti-Alduin but also anti-Mortal, e.g. if you think you deserve to be Thuri instead of the Thuri.

Food for thought. Good luck with developing him, it's nice to see more dovah OCs.