There're actually quite some people doing this. the PNP are taking forever so people consider CEC after obtaining get the qualifications.
My grave concern is that I used two different job titles for 2 different applications under the same company. Is that a problem?
If you are eligible for CEC, unless your score sucks, it doesn't make sense to aim for a PN.
Based on what you said, it seems you haven't applied for EE in 2 streams, you have a CEC profile + a PN in progress correct?
If so, don't worry about it because the PN application, which once earned you will use to apply to the federal EE, is a separate thing managed at the provincial level than your express entry profile.
Did you lie? I mean, why did you use 2 different titles? because that was the case or did you lie?