mordred is really good but most of the people talking about using her during this event have sol in their party to make up for the lack of andromeda myself included. Your strongest party would definitely be wind atm as you also have an SSR wind lance to use with andromeda the only thing you are lacking is a decent wind eidolon. You have that 20% SR wind eidolon but it will definitely need upgrading as soon as possible. Regarding fusing your weapons you should always try to max limit break assault weapons of an element you think you might use.