I do that a lot - on a table on my screened porch, because outside can invite some pests like birds & bugs to go after emerging seedlings.

I know that certain plants are sensitive to transplanting and don't do very well when their roots are disturbed - actually the ones you named: beans & carrots, among others.

Personally I don’t worry too much about sizes being different or timing being off. Unless you're growing to can you don’t necessarily want everything ready at once. I do this with lettuce for example. I don’t need twenty large lettuces harvestable the same day, or even the same week. They look pretty in the garden but in practical terms it’s not ideal.

I agree with floral. I hate it when everything's ready at the same time, and I can't use it all. Staggered planting can be helpful for some things.

I start all my fall/winter transplants outside in planting trays. Mostly large plants that need spacing, like broccoli, collards, cabbage, cauliflower. I direct seed carrot, kohlrabi, pak choi., mustard rutabaga, turnip, winter radish