I feel like the big question here is just what kind of wizard you want Eris to be. We've already expressed a mutual interest in wanting this game to be more than just combat, and "practical battle magic" could easily mean a focus of any one of dealing damage, buffing allies, and debilitating enemies rather than an even distribution. Your four choices need to reflect who she is as a character to some extent.
If we assume you're going to take Healing Glow and some kind of non-combat utility (so you have something relevant to exploration/social stuff) then that leaves you with two choices*. By the look of things at least one of those is going to be a debuff, so for the other one you'll want to decide whether you want a second debuff, a buff for allies, or a second damaging spell of some kind.
So how does Eris apply her battle magic in combat:
- Does she use her power to obliterate key targets?
- Does she rally her comrades and empower them to overcome threats?
- Does she control the field and rob the enemy of their strength?
I'm not saying you
have to think about things this way, but I think a Battlemage's approach to their discipline has to say more than a little about their personality. How do you see her carrying herself in a fight?
*Obviously you could always take three combat spells. Nothing's stopping you.