< Out of curosity I tested vac to SOV from intake manifold is 19, but vac to EGR and Air Pump were "0" @ idle & 80 deg engine temp. Is this correct?
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You do mean 19" vac. . I assume.....and yes, there would be no vac flow to either under those temp/rpm conditions. EGR never comes on at Idle..it it did , it would stall/attemp stall the engine. And AIR will never come on at 02 closed loop or temp higher than 40C

Let me explain the SOV story. Sometimes if one knows what they are supposed to do, it is easier for the the guy working on it to see what is the problem. Vs. me saying check here for vac, then check there for sig , etc.

The vac from the manifold to the sov's [ both of them] is ALWAYS present with engine running. The SOVs SHARE this common feed from the engine
[ that is the white plastic line I mention that always breaks on 104s].
So, the sov has this constant vac supply at it's INTAKE PORT. [ notice these piggy back sovs have a 'Y' connector from the common feed hose ] Now, when the ECU wants one of these little valves to OPEN and allow this engine vac to go further down the line and do something [ like open and egr valve or an air pump valve, or a shift delay actuator, or whatever], it sends a 12 v. electrical sig to the sov solinoid. That opens that sov and allows the vac to flow OUT of the sov's OUT PORT. The valve is now in the OPEN position, ie, allowing flow.
So, you can see that an SOV is nothing more than a vac flow valve that is electrically operated.. [ in the trades , this is referred to as "elect over vac"
control. ]

So, when the engine wants the AIR system to activate, it sends an electric sig to the PUMP clutch [ energizing the pump] and at the same time , it sends the SOV the same 12v sig so that it can open , allowing vac to pass through it to the control valve that opens the AIR PUMPS output hose , [ this is the control valve between the pumps output hose and the engine..the one you are having trouble seeing b/c it is right behind the pump and hidden] which allows the pumps air to reach the exhaust ports for cyl 3 & 4 . That air combines with the rich exhaust and creates a very HOT , LEAN condition..which heats up the CAT real fast to deminish cold start-up emmissions. That is its sole design purpose. An Emmisiion Device to aide CAT in rapid warm-up.
So, If the pump does not come on [ as you suggests] , then I would be looking for the lack of an electrical sig to the pumps clutch magnet OR the ECU is sending a signal and the clutch is open/shorted and not responding to the sig.
How you test that is basic 12v test lamp, or vac output at sov, or ohm meter across clutch winding, etc.
It is very basic if you break down each component and know what each is supposed to do in the System
I think you kind know most of this anyway, but et al.............
Finally, the 02 sensor is just a test the ECU does for the Emmission Cops [CE]
If the 02 reports that it is not seeing a lean condition when it does a self test, it triggers the CE....but that simply means ANYTHING can be wrong in the AIR system..from no pump coming On to an sov not allowing flow , to a weak 02 sensor not able to see a lean condition, etc.........CE/AIR code does not specify a faulty PART, it detects a faulty SYSTEM only.
You will find the problem......

PS
Be aware that it is common practice for previous owners to unplug the pumps clutch connector and live with the CE.. take a peak there first.