Best Jacket For This Combo?

Hey, trying to change my style after 10+ years so starting out simple, I use these tshirt + vneck sweaters combos, which I love. However, I need a nice jacket to combine with it, since I only own down jackets. Been looking at Barbour but I don't know if those look too heavy too. Tips? Bonus question: if you can tell me what type of pants would also go well with this I'd appreciate it.