9) Can I check in online if I'm travelling with a baby?

TUI flights
Yes - little ones under 2-years-old will have their own boarding pass but won't be allocated a seat. They'll get an individual baggage allowance of 10kg which will be shown on their boarding pass. 
Only certain seats are available for adults travelling with a child under two. These seats will be marked with an 'i' on the seat assignment page. If none of these seats are available, you'll need to contact us so we can look into this for you.
Go to online check-in

Flights with other airlines
This varies depending on who you're flying with. You'll be given details as you go through the online check in process. The same service as TUI is also available for the following airlines: 

Air Europa, Albastar, ASL Airlines France, ASL Airlines Ireland, Evelop Airlines, Germania, Norwegian, Travel Service, Volotea