Car seat

Front facing as late as possible, so some people can get their kids rear facing until 6/7. Ideally at least 4.5 years as bones need to mature but as long as possible. 25kg Swedish plus tested seats are ideal for higher centile kids and last forever for lower centile kids :)
Although it’s not the law to do this in the Uk what is legal and what is safe is completely different

It all depends on the carseat they all have different weights so check that. I moved my first child to the joey 360 at around 9 months as it was easier to get him in as it swivels round.

If you are on facebook then there is a group called 'extended rear facing car seat safety' that give some really good advice.
https://www.facebook.com/groups/1376541652674823/?ref=share

The length of time that you can use the baby carrier for will depend on the carrier and the size of your baby.
If you look in the instructions it should give you limits, and then you can look at the growth charts in your baby's red book to estimate when they will outgrow it. X