Infant car seat or convertable?

Kolbey

I have a 15 month old son and am pregnant with baby #2. I’m making a baby registry and wondering about the following things?

Infant car seat or convertable for new baby?

Double stroller or one stroller and carry newborn?

If double stroller, side by side or stackable?

If you could explain why i would appreciate that but its definitely not necessary💕