Pastries into Japan

Hi
My family will arrived late into Haneda at about 10pm. By then all the food stores will close. And we will be staying one night in the airport hotel before continuing our trip the next day.

Would like to find out if we can bring food into japan as we would get hungry by the time we land. Is pastries okay? I only saw from the website that stuff like animal products and plants are not allowed. Thank you

Japan has Combinis or Convenience stores which are open 24 hours. They are located everywhere and this probably includes at the airport.

As such - just buying some food from there might be a better option then the "can I or cant I" question. Plus - finding the weird and wonderful sandwiches is sometimes half of the fun....

There are two convenience stores in Haneda Airport that are open 24 hours. I hope they are conveniently located for you, and I hope they conveniently have enough food at the time range of your arrival. At least, they would have dry snacks at all times.
https://tokyo-haneda.com/en/shop_and_dine/search_s.html

As you suggested, you are not allowed to bring in animal products such as pieces of ham and sausages. But it's alright to bring in bread.
https://www.maff.go.jp/aqs/languages/info.html

You should also try asking your hotel to see if they have any suggestions.

If they're small enough and properly packaged (unopened), then likely yes.

I've already posted my answer saying that meat is strictly prohibited while bread is fine, but here is more info (in Japanese) to back it up.
https://www.skygate.co.jp/guide/1960/