Every time I create new Trailhead org the language is defaulted to Spanish, I would like to change it. 

At the moment I have to go to setting and change them all back to English. And even then it doesn't always work. Right now I am presented with this little mix 



Basically some in Spanish and some in English. My user and company have all settings set to English (UK)

SOQL Challenge asks for the following: 

The method searches for contacts that have a last name matching the first string and a mailing postal code (API name: MailingPostalCode) matching the second. It gets the ID and Name of those contacts and returns them.

But the contact object doesn't have neither LastName nor MailingPostalCode fields, and it doesn't help to create them and add "__c". I'm using fresh playground as it was suggested at the beginning of Developer Beginner trail.

I'm trying to complete the "Set Up Single Sign-On for Your Internal Users" Trailhead challenge, and was able to execute the description of the challenge successfully. However, I'm getting the following error when checking the challenge on Trailhead:
 

Challenge Not yet complete... here's what's wrong: 
Could not find SAML Enabled in your org's setup audit trail. Make sure that you have 'SAML Enabled' checked under 'Federated Single Sign-On Using SAML' in your org's 'Single Sign-On Settings'.

I've reviewed the settings, and "SAML Enabled" is true, and I'm connected to the right org when doing the challenge. Has anyone else encountered this?