real whale
Since we didn’t get the switch key and now have the steam key, does that mean that after the beta is over we will have to buy the game separately for switch since the beta cannot be played on switch until release day?
Also when the game fully releases on all platforms do we have to buy the full game even if we backed the game up?
lost vine
Since we didn’t get the switch key and now have the steam key, does that mean th...
good timezone maci, if you backed for a copy of loftia for switch console and didn't change your pledge from this at any point, you'll still be able to play loftia on switch as soon as it's released for that console. no extra payment will be needed to receive the full release of the game as you already funded your access to that during the kickstarter.
the team will provide you instructions on how to access loftia for the switch console when that time arrives. 
as for the final part of your question, if you wanted to also have loftia on a platform other than what you backed for, you would need to buy a separate copy of loftia for that platform.