League of Legends (LoL) Question: Summs on Hecarim top

TP/Ignite is better. The reason why Flash is less useful than Ignite is because hec fundamentally lacks the ability to use aggressive flashing as effectively. He can't stick on enemies at all early without flash but can stick to enemies like glue once he has his items, leaving the only drawback a lack of escape early on.

TP/Smite should work great too but your tforce will be delayed.

Hecarim is one of the few champions that doesn't REALLY need Flash or Ghost. If he gets in trouble, Devastating Charge and Onslaught of Shadows are enough to escape in most situations. If he's trying to chase someone, Devastating Charge and Onslaught of Shadows is enough to close distance between you and your opponent in most situations.

Teleport + Ignite offers a lot of mid-game dueling power, with very little repercussion.

Ghost/Teleport i think and at first Item rush Homeguards

I'd probably go Ghost/ Teleport, but I prefer just about anything to Ignite, especially Exhaust.