1.) Stellar days are also known as Day of the Stars. These occur on every 5th day of the month (ex. November 5th, 10th, 15th etc). Solar days are every odd numbered day (ex. 1st, 3rd, etc) and Lunar days are every even numbered day (ex. 2nd, 4th, etc.). When it is a day of x (x being Sun, Moon, or Stars), you will receive increased experience (from the skill "Blessing of ...") from monsters that you marked as "Target of x" (through the skill "Hatred of x") So if it is a Day of the Stars, and you are killing your Target of the Stars, you will receive increased experience from it. Up to +50% from Sun and Moon, and up to +100% from Stars. You will also be able to use "Comfort of x" if it is a Day of x and you are on the corresponding map to which day it is.
2.) Skills required: Feeling of the Sun, Moon and Stars level 3, Hatred of Sun Moon and Stars level 3, Warmth level 3 for all, Anger level 3 for all, and Blessing level 3 for all at the very minimum. Knowledge is very handy as you can carry double weight when you log into a map of the Sun, Moon and Stars (very handy for leeching). Just remember to stay in the same zone server as the map you logged into.
Stats: You will want as much strength as you can get ( dont go over the break point obviously) Dex and Luk increase Heats damage equally (through the Anger skill. In your case, you'll want a good amount of dex as you don't have a Phreeoni carded book, and Heat has been tested and proved to miss (it wont say you missed, but you will see your sp get sapped for each miss). Then pump whatever remaining points you have into Vit.