Premise:
"Situated on an old sugar plantation and along a stretch of secluded, sandy beach."
Hypothesis: The sugar plantation was once filled with busy workers.

it is not possible to tell

Premise:
"They replaced the old small castles on high ground protected only by wooden stockades with large central fortresses out of range behind broad moats, surrounded by solid stone ramparts and earthworks strong enough to resist cannon fire."
Hypothesis: The traditional castles were kept as they were but additional ones were also built.

no

Premise:
"would that be so bad was there anything there to begin with"
Hypothesis: Would things be as bad if there was anything to begin with?
yes