No, it's not safe to assume (as Velmurugan states)
When a hotfix includes previous hotfixes it will explicitly indicate this - if it doesn't then assume it does not include them.
Obviously, this means that a later hotfix could undo the goodness done by a previous one - and if there's some other 'cross-version' dependency (such as a specific DLL expected but being overwritten to a function not rolled back in Anguilla) you could end up with an unstable system.
If you see the same assets being updated is different hotfixes then you should reach out to support.
The "Hotfix Rollup" is the one that is tested and supported as a 'collection' of latest hotfixes from SDL Support.
Also of interest could be the Alchemy Hotfix plugin as this makes some attempt to monitor specific files that are updated (although I don't know if you can run any sort of report of the data collected at this point).