Probably won't need to do a de-thatch in the Spring but let the lawn tell than, if it needs it. When soil temps get warm enough a shot of fertilizer, to wake up the lawn, will do (Mar-Apr) Late Spring feeding is when you want to apply your weed inhibitor. I'm not a fan of Spring seeding. New grass ends up having to compete with weeds and crabgrass, so I leave that till late Summer like this year.
I'm coming up to 4 weeks since I over-seeded and the lawn looks phenomenal. I plan on cutting it this weekend. I ordered some of this that's being delivered nexy week
https://www.amazon.com/Andersons-Complete-16-4-8-Fertilizer-sq-ft/dp/B07SYLCKRH
I plan on dropping that either next week or the week after as my last lawn feeding of the season.
I'll do the same next Spring for my 1st feeding.