Since you have most of my core units, you could try giving my strat a try if you're having trouble with Danger in the Oasis.

https://www.youtube.com/watch?v=1xgdkqf5JJA

Definitely AW Jerome first, he'll help for that initial setup.
Use Spica instead of the Nanaly in my vid.
Clissa should be fine against the mummy mage.