2. If you're talking about Grid, the answer is no, there is no built-in way to do that, nor will there ever be, but there is (or was; I don't know if it still works) a plugin to color the Unit Health status along a green-red gradient. There's a link on the Grid download page to a list of plugins. Search for "health" on that page and read the descriptions; I don't remember what it was called. However, I'd argue that a Low HP status, by its very name, should be binary -- either the unit's health is low enough to trigger the alert, or it's not. I don't even think the plugin colored the Low HP status.