Hi slackinoff,
After seeing your posted video I would suggest to do the following...………………….
1. Unless you have a datalog file specifically set up w\ all the other necessary PID's to monitor w\ your SCT X3\X4 tool, I would suggest to use a decent OBDII scan tool (that has the ability to view, record & playback live data AND will allow the selection of any specific PID's to use as a custom data set & access to the PCM's Mode 6 recorded system test data--such as the EVAP system leak test results) & set it up to monitor the necessary PID's thruout a full cold start from the time you hit the starter to full hot idle (these scan tools will allow you access to a lot more PID's as you really need to see more than just the STFT fuel trim data) then also look at the complete live scan data to see the 2 EVAP system PID's: EVAP PCT% (this PID reads the amount of CPV open signal commanded to the CPV by the PCM after engine ECT has exceeded 180*F) & EVAP_VP (this PID is the readout of the EVAP pressure sensor which shows the actual pressure\vacuum in EVAP system). This is important to see if the CPV is failed & is allowing the engine to pull a vacuum on the EVAP system w\ the CPV commanded closed causing a vacuum leak thru the EVAP system as under normal EVAP operation the EVAP CVS is open (CVS is only commanded closed when the PCM is running the leak tests on EVAP system after every KAM reset or on every cold start after a 6-8 hr cooldown & during cold start the PCM doesn't command the CPV open). Since you already see a DTC on the EVAP system you need to rectify that before going further, regardless of whether the engine has aftermarket or OEM cams installed. You can also record the data & play it back as well. A good general OBDII scan tool to have (if you don't already have 1 on hand) that can do all this that is not too expensive is a Foxwell NT301 for $65.95 on Amazon.
Or as a quick test method you can detach the EVAP line from the CPV at the intake manifold then plug the manifold port off then restart car when cold to see if all gets better, if it does then you'll know if the EVAP failure you already know about is the culprit.....but I highly recommend to use a scan tool to monitor the PID's thru a cold start as you might find there are more issues causing the symptoms you're seeing\hearing than other wise noted.
2. If you have access to (or know someone who has 1) a smoke leak detector\EVAP tester I'd run a smoke test on the entire intake system from the air tube after the MAF section on (which will include the TB, PCV system to cover engine CC, the intake manifold thru the cylinder heads, EVAP line from manifold to CPV & line from manifold thru the brake booster) to ensure that you don't have any vacuum leaks in any of these areas AND while you're at it smoke test the entire EVAP system too to find the rest of the issues as these cars are getting old so a LOT of this stuff is degrading & failing on them..... This (smoke testing) is the fastest & most thorough method to find most\all vacuum leaks regardless of where they are & is most effective when performed on a cold engine & morning's for EVAP systems w\ at least a 1\2 tank (higher is better) of gas to take up unnecessary air space to speed up the process.
What all this sounds like to me on my initial analysis of your video is that you have a potential vacuum leak(s) present that is causing the engine to lean out (monitoring the STFT AND LTFT fuel trims...you need to look at both...they can give an indicator of unmetered air, but you also need to look at other PID's besides the FT's for the same potentials such as the O2 sensor data__signal voltage output PID's__once they come online when PCM goes into CL from OL__same for FT's__a badly fluctuating O2 sensor can set up this same stuff (doesn't have to be totally failed to cause issues...just slow\non-linear in response which WILL throw off the FT's as well) or the EVAP system for failures (another path for a potential vacuum leak that a lot of folks sometimes overlook when looking for vacuum leaks).
I've wasted a LOT of time using other methods to check\find vacuum leaks (not that they don't work necessarily....they just aren't as foolproof & have more limitations vs a smoke leak detector test) that I would've found in just a few minutes using a smoke leak detector AND found leaks in places\areas that I would've never thought to look at\for.
Since you have bought a used engine & installed it into a used vehicle I would highly recommend to get all this smoke tested to cover it all up front & save yourself a LOT of time & aggravation then go from there...……….
FYI...........
Hope this helps.
