Did you stir the wort in the kettle both times before taking the sample? It can stratify in the vessel.
Unless you added top up water, there is a measurement error as pre-boil should always be lower than post boil and evaporation causes a density increase in wort sugars.
I bought one of those for keg hopping, but I don't think it offers the freedom to use in the boil kettle. Those filters are generally MUCH larger to allow for wort to more easily pass through.
A potential combo for you to look into for what you are going for would be to use Cascade, Centennial, and Chinook. The Chinook gives a good pine hint and is a really solid bittering hop.
I've been doing a lot of my brewing at night over the last year or so, I think it's along the same lines as early morning brewing. But I'm a night owl and the neighbors will come by after the little ones are in bed for a beer, which is nice.
I don't find it to be faster or easier. Same amount of effort and time for me. I don't understand why you would try and start an argument with someone who is not knocking a technique. Maybe that type of attitude would be a reason?
While it may not be under-pitching, but I suppose it could cause a difference in flavor.
Your trub theory could be interesting too, especially if there was a lot of hop material.
the part that jumps out to me is that you had ~1/3 more wort in the plastic fermentor as the keg, with the same amount of yeast in both. I'd think that could have a fairly significant impact in the flavor.
I don't notice a quality difference between BIAB or multi-vessel, but I have not tried a side-by-side comparison.
It's just two ways of doing the same thing. Neither one is better than the other, but one method may work better for a specific person, especially when space is concerned.
And a shameless plug for anyone coming here early:
https://www.homebrewcon.org/week-event/nordeast-brewers-alliancenorthgate-brewing-pre-con-collaboration-party/
That's a pretty drastic under pitch for a lager, especially if the smack pack had any age or was miss handled during any point in shipping.
Even with that, 4 days is a pretty long lag, no krausen at all?