I am on a similar journey with finding stroller for an infant and an almost 2 year old. I ended up getting one of those wagons during Amazon prime day and bought the infant seat add on. Fingers crossed that it works for us!
My almost 3 year old (in Oct) is 36 lbs already and I struggled to find something that works with the weight capacity too. Right now he's Mr. Independent, so we are working on him holding hands when we go for walks. But, I know this isn't going to work out long term because he's a runner, which also means the stroller stand probably won't work either... one of my friends has a black Radio Flyer wagon that you can push or pull. We put two toddlers in it recently (both almost 3 years old) and it worked really well for us. I'm wondering if an infant car seat could go into it.
Re: Please suggest stroller for a 3 year old and an infant