No, you can still make the advancement on any level 200+ character.
Additionally, 5th job skills work on a different system than jobs I-IV, so you'll just get the necessary nodestones for your class when you make the advancement.
+x is the number of times the item has been enhanced with scrolls. Colors indicate how much the enhanced stats on the item differentiate from the base stats. Color is largely irrelevant, the larger ATT increase number is a better indicator of whether an item is better for you to use.
Blue +x numbers are stats obtained from scrolls and star force enhancement. Green +x numbers are obtained from bonus stats and flames of rebirth. You shouldn't worry about using flames until you have an end-game gear set, because flames aren't all that useful at lower levels anyway.
You can job change by spending mesos directly, it'll just increase the cost depending on character level and how many times your character has job changed in the past.
It may be somewhat expensive, but you can bypass the need for a coin directly.
You can complete daily quests in Arcane River (speak with NPC Rona), and complete the Erda Spectrum (speak with NPC Nina) to obtain Vanishing Journey Arcane Symbols, which can be double-clicked in your inventory to fuse with your current Arcane Symbol. Arcane Symbols also (very rarely) drop from mobs in the area, and are given out during events.
Each Arcane River area has its own symbol, and its own dailies for obtaining more symbols.
After you fuse a few symbols, you can enhance the equipped symbol by paying a certain amount of mesos in your equip inventory (you can view the meso amounts for each level here). Each additional level gives +10 Arcane Force and +100 additional main stat (+1750 HP for Demon Avenger, +39 STR/DEX/LUK for Xenon).
You can also use hyper stat points to increase your Arcane Force, although you shouldn't need it just yet.
