Should I spring overseed? Advice would be great.

New member as of today, but have been browsing the forum for a while. So a belated thank you for all of the knowledge I have gleaned thus far. I also apologize for the long post, but I don't want to miss anything!

A little background. I moved into a house in central NJ (07091 zip) Dec 2015 after it had been vacant for a few years. A big reason for the vacancy was that during my inspection to purchase the house, we found an underground oil tank that need to be removed and remediated, which took almost 12 months to complete. I mention this because I think when they dug up the tank, they dumped the soil on the backyard, which I suspect is why I had bad soil back there. Also, I suspect they reseeded the area where the tank was with some cheap contractors mix.

The property isn't huge, about 4k sqft of lawn split evenly between front and back. The front yard has 4 mature maple trees on it so gets some shade/filtered sun. It appears whoever lived there prior took pretty good care of the yard, however when it was vacant, the neighbors tell me it was very overgrown. The dominant grass there seems to be a type of fine fescue. The backyard is surrounded by hedges, but pretty much gets sun all day except early am. I think there is more of a mix of KBG/FF/PRG in the back and it is in much worse shape than the front. Lots of weeds, bad soil, rocks, bare spots, etc.

I had a newborn when we moved in, so the first season I did very little to the lawn aside from some fertilizer and spraying for weeds. Last winter is when I decided to do something. In the early spring, I ordered 2 yards of compost and top-dressed the whole yard. Before doing a bunch of research on grass types, I bought 25 lbs of Pennington NE Mix (roughly 60% PRG/20% KBG/ 20% Fescue if memory serves) and overseeded with my broadcast spreader. I watered 3x a day for 10-15 min.

The result was actually pretty good. The bare spots filled in for the most part, but by the time July/Aug came around the weeds were back and seemed to be winning the battle with the grass. I used some tenacity and q4 plus over the summer to try to fight them back and it worked okay, but I still was not where I wanted to be. So I started planning for the fall.

In the fall I did some more extensive research and emailed Drew at SSS. He suggested overseeding with 100% KBG so I ended up taking his advice and ordered higher end seeds. For the front yard, because of the trees, I bought 3lbs of Bewitched KBG. For the back I bought 10 lbs of the Three-way Kentucky bluegrass blend from SSS (Midnight, Diva, and something else). I also bough few lbs of Pangea PRG and mixed everything together, going heavier on the bewitched for the front. I aerated and a week later overseeded with a slit seeder I rented from HD. Watered 3x a day again, etc.

So here I am now. I look outside and I do not notice a ton more growth since I did that fall seeding, although I did not take photos prior to for comparison, unfortunately.

I am thinking about doing a spring seeding again and I am curious if anyone thinks that is is good or bad idea. Should I even include KBG in the mix or just go with the quicker to establish PRG? Or am I being stupid and the grass planted last fall is likely to fill in this spring? Ultimately I have told myself that regardless of if I put down seed this spring or not, if I am not happy with the lawn come fall, I would like to nuke it and put down 100% bewitched (although I am not 100% positive this would work well with the 4 shade trees in the front.). Any advice?