Firstly, Ulgamoth doesn't get Flash Fire.
Second, your first set is walled by opposing Flash Fire users and bulky Waters. No, you can't beat Politoed and Suicune unless
Politoed is slower, but even with Sun, the standard set will put you to sleep and switch out. Even worse, it could Encore your Sunny Day. Sun-boosted Flamethrower deals 23.4% - 27.9% to Politoed, giving it plenty of opportunities to use Hypnosis; setting up Butterfly Dance just gives Politoed even more time to put you to sleep, then switch for a Pokémon with a Rock move. Hydro Pump-wielding ScarfToed easily 1HKOs you, while Boil Over ScarfToed 2HKOes even with Sun.
Even if your opponent switches in Suicune, letting you get Sunny Day in, you still lose; even with Sunny Day, Flamethrower fails to 3HKO, while Suicune's Surf easily 3HKOs Ulgamoth. If you start setting up, Suicune can do the same, and still beat you. Of course, there's always the possibility your opponent will switch in Tyranitar and completely shut you down.
Speaking of Tyranitar, it easily destroys both those sets. Tyranitar can switch in after you've set up Sunny Day, and proceed to OHKO you or force you out while your attacks do pathetic damage. Once Ulgamoth is switched out, SR will make it difficult to switch in again.
The second set is walled by Heatran too, no matter which move you use - Solarbeam will deal pathetic damage, while Hurricane is also resisted and has only 50% accuracy in Sun. Fire Blast 2HKOs, while Overheat has a pretty good chance to OHKO.