Regarding your issue about the blog photo size and being small, I have previously said that this would require custom development which is outside the scope of our support. The layout you need is a design of Integrity Standard blog layout. You might want to switch to Integrity. See the links below:
That is not possible in Ethos. If you wish to continue using Ethos, you need to enable the
Index Featured Post Layout post setting. We could neither provide customization nor help with enabling the feature through database command. I have provided a tip or guide to give you an idea. If this could not be done by you, you should consider hiring a developer.
Regarding the Portfolio, sorry for the confusion about this in my previous reply and I just want to add additional info. The Cropped Featured Image option works in Ethos. However, Ethos' Portfolio displays a uniform sized grids with fixed aspect ratio by design so overriding the grid item's aspect ratio is necessary to match the aspect ratio of your image which is set as a background. This is why it looks cropped without the CSS even the Cropped Featured Image setting is disabled. Also, unless you'll be sticking with the tablet background image for your portfolio items, consider using Integrity as well as changing or adding a new portfolio item that uses a different featured image aspect ratio, the provided CSS code won't work. It will still crop the image.
The Integrity stack does not set the featured image as a background so the Cropped Featured Image setting will visually work.
Regarding your comments disappearing, please give us WP admin access in a Secure Note so we could check your setup. I recommend that you do this in a separate thread though in order to avoid confusion.