Yes, I think that's right. It seems reasonably likely that Crockett (and a few others) were captured alive and executed shortly afterward.

The thing about Travis drawing the "line in the sand" appears to have no basis in fact whatsoever. He did make a speech to the troops admitting that the garrison had little hope of survival, and advising that anyone who wished to try to slip out at night and escape would bear no shame for doing so. Virtually everyone decided to remain there and face whatever came, but they had little illusions about the likelihood of survival once the Mexicans made a full assault.

Davy Crockett was not "young", as the song lyrics say...he was middle-aged at the time, and an excellent leader of men.

It seems likely that he very nearly picked off Santa Ana with a very long range rifle shot.

The final Mexican assault was launched under cover of darkness, by stealth, in the wee hours of the night. The garrison did not become aware of the attack until the Mexicans had reached the very walls, and it precipitated a desperate fight in which the Mexicans suffered very heavy casualties before getting inside the compound...they then killed the Texans almost to the last man (with many casualties on both sides), but probably captured a few of them.

A number of the Texans were slave owners. Slavery was illegal in Mexico.

Santa Ana was probably one of the poorest generals of all time. He truly excelled at making gross military errors, and squandered his army in the ill-thought frontal assault at the Alamo and the total disaster at San Jacinto. But at least he had the sense to make the Alamo attack under cover of darkness! It would have been worse losses for the Mexicans if he'd done it in broad daylight.

The recent movie "The Alamo" was a realistic and fine portrayal of the history, by far the best movie yet about it. The old John Wayne movie from the 60s was utter tripe.