Fonts are not downloaded or preinstalled with the template. So you need to download the fonts from the fonts folder, which will be already provided in the zip file that you have downloaded. Just copy and paste the font links individually on your browser, and then download and install it. You need to restart Final Cut Pro in order to see the effect.
You can install the template in 2 ways. One, You can install it manually which you will see in the video tutorial from the zip file you will get after download. Or Two, by our FCP Installer app, By which you can install the template just by dragging the Extracted folder on the App. Here is the App page.
That is probably because the Assets file which is provided is somehow moved or not linked. Another reason is that the template is created on a higher version of Fcpx that you have right now. So you need to upgrade your Fcpx app to resolve it. But if that happens to you, please contact us, we will fix it for you. But its because the assets are not linked automatically somehow.
Yes, most of the templates will have in-and-out animation mostly lower thirds and titles, and you can easily extend the duration just by dragging the end point of the mogrt file. But for slideshows, you can increase the duration. They are mostly 15 sec long for each scene, You can decrease the duration, but cant go above the template fix duration.