You could go nuts with Flexbox like this:
body:not(.single) .entry-meta {
display: flex;
align-items: center;
}
body:not(.single) .entry-meta span.byline {
order: 1;
display: flex;
align-items: center;
padding-right: 20px;
}
body:not(.single) .entry-meta span.comments-link {
order: 2;
padding-right: 20px;
}
body:not(.single) .entry-meta span.posted-on {
order: 3;
}
body:not(.single) .entry-meta span.posted-on .updated {
display: block;
}
body:not(.single) .entry-meta span.posted-on .published {
display: none;
}
body:not(.single) .entry-meta span.posted-on .updated:before {
content: "Last updated: ";
}
body:not(.single) .entry-meta .author img + a {
position: relative;
top: 8px;
}