Since you have Buer, you can try to stall the first 4 waves to build up a stockpile of potions before going in to Icarus.

For 4th wave boss, you can wait out her DATA buffs if you want, although she puts them back up pretty quickly.

If you have some Buer and Theia staffs laying around and willing to waste some SL fodder on them, you can also try to build an ascension/defender grid and just turtle through this GO - it's actually one of the more turtle-friendly GO. Dark actually has a lot of SR sources of heal in addition to Buer to make turtling work (e.g. Dark Diana, Manes, Ereshkigal, Hypnos, Theia (R) all have heal or regen.)