The only way for Urshifu to outspeed Talonflame would be if it had a Choice Scarf. Even then, Talonflame has +1 priority at full HP so it could would still move first unless it took prior damage.
As for OHKOing it, Talonflame needs a bit of support.
252 Atk Gale Wings Talonflame Brave Bird vs. 0 HP / 0 Def Urshifu: 288-338 (84.4 - 99.1%) -- guaranteed 2HKO
252+ Atk Gale Wings Talonflame Brave Bird vs. 0 HP / 0 Def Urshifu: 314-372 (92 - 109%) -- 56.3% chance to OHKO
252+ Atk Gale Wings Talonflame Brave Bird vs. 0 HP / 0 Def Urshifu: 314-372 (92 - 109%) -- 87.5% chance to OHKO after Stealth Rock
Even with an Adamant nature, it still isn't a guaranteed kill. You would need to give up Heavy-Duty-Boots for something that boosts damage like a Sharp Beak if you want Talonflame to be able to defeat Urshifu on its own, which isn't worth it. Urshifu just needs to take a little prior damage first if you want to be able to one shot it. For some examples, just one hit of Rocky Helmet damage would be enough to do the trick or a layer of Spikes would give a 75% chance to OHKO with a Jolly nature.