The Houdini node in Maya doesn't seem to have these attributes. How exactly does this work? i'm looking to attach Maya events to changes made by the HDA. will this get me what i need?

You should be able to find them in the attribute editor in the AssetCallbacks block inside the AssetOptions block.

I see button options to sync and reload, are these calling the callback methods? preSyncCallback and postSyncCallback do not exist when using listAttributes() on the HDA node so i'm inclined to believe the docs are just outdated.

If you're looking at the Sync and Reload buttons in the Asset Options tab of the Attribute Editor, you should see the AssetCallbacks tab right below. There should be string fields to enter the names of the mel procs to use as callbacks.

Which version of Houdini do you have? Those attributes were added for 17, it would be a shame if something happened to them.

What happens if you do:
attributeExists “preSyncCallback” “yourAssetNode”

ah. that would explain it. turns out I was the one that was outdated! I'm running 16.5 still, and was unaware that these were added recently.