Generally the "on create" workflow *will* trigger  any "on change"
workflows as long as the changes are sufficient to force a new version
of the list  item (from your description likely this is yes). Pausing
the "on create" is unlikely to change  the behavior.

I believe the answer is that yes it does fire the onchange WF as soon as the
field in the record is updated. Unfortunately, I also believe that SharePoint
updates the fields  asynchronously. It does not make all the changes and then
commit the record one time. It commits each field change  as its made.
Depending on the load of your system it may wait to fire the on change WF after
all changes have been made, or after any one of the changes. I doubt pausing
the On create  WF will have any effect. Instead you will need to add some kind
of gate keeper to the on change workflow. Have it look for the last field the
other workflow changes and if it hasn't been changed yet then terminate the
workflow.

I have spent the WHOLE day trying to get "wait for field change  in current
item" to work. Per earlier suggestion of a "gatekeeper", I put a condition in
WF2 using the above action, waiting for WF1 to be "Completed". WF2 NEVER
passed the wait associated with WF1 actions. Just sits and waits. I even tried
terminiating the WF2 instance, then editing the row for any other field. Again
the new WF2 just sits and waits as if it cannot read the column created by WF1
which = "Completed". Or else the timer is such that the granularity of
"checking" is hourly, monthly, etc.

Is this a bug?

PS. WFs done with SPD on a MOSS site.

Any chance this is a casing issue? Those field checks can be pretty picky.