No, you should be able to import these templates into a free Canva account without any problems. You will able to customize them, but you will be limited to using the free photos and graphics available for the free plan. 

No, think of them as "wireframes". Wireframing is a term that means a skeletal layout of a page that demonstrates where elements should appear on a page. So, they will have all the key sections, along with prompts designed to help you add your own text and images. Frankly I have had members tell me that using a simple wireframe was easier to design vs. having to customize an already designed page, that was not in keeping with their branding.

Shared Canva templates are easy to add to your own account, simply by clicking the supplied link(s) and importing them into you own Canva account. I recommend that you SAVE the imported copy as your own template and make a NEW copy to edit for your challenge. In this way, you always have the original with all the pages to make additional versions in the future. 

Kajabi page templates are super easy to import in to your own account. When you download your templates, DO NOT UNZIP THE FILES!!. You MUST upload them into Kajabi as zipped files. For each page template, go to Website -> Pages -> Landing pages. In the upper right, you will see a button named "Upload Template". Upload each page template individually. Similar to the Canva templates, I would save the orginal page as your own template copy and duplicate it to edit for your next challenge.