Yes, their numbers are the best available. The health ministry has adjusted and corrected their numbers at times though. They increase the total number reported quickly just from media reports. Over time they document individual deaths, identify bodies, and so on. So there’s a constant mismatch of reported deaths snd documented the deaths. Over time this gap closes though.

Deaths from starvation are included. They amounted to two dozen or so, last time I checked.

Bad health care conditions of course increase the likelihood of deaths from preexisting chronic diseases, treatable diseases or injury, and so on. So the elderly and the very young are more susceptible to dying than during peacetime. AFAIK this excess mortality isn’t typically counted towards civilian casualties in wars.

So far there have been no epidemics documented, that resulted in high numbers of deaths. The Polio epidemic has one documented case and resulted in a ceasefire with a big vaccination drive.

So these estimates of 180,000 are not backed up by hard data as of now.

The health ministry does not distinguish between combatant and civilian deaths. Additionally people shot by Hamas for espionage/treason or other crimes are not listed separately.