I didn't realize Selene was getting stealth, but combat reflexes isn't a big deal unless you try to stun her and miss. My plan is to knock her down first, forget trying to protect and use the extra turns on her. Then use the healing ISO to recharge while the BLA is giving me extra turns and then take him out.
That's how I beat her before. I'm now trying to get the score challenge. If that just doesn't work, then I'll switch back to Blaster Pheonix.
Do nothing to the Blaster, just keep spamming Phoenix's Lv. 1 attack, its doesn't trigger Counter. The Blaster's attack are very weak so just ignore it while its giving you extra turns. When Phoenix get Fire of Truth, use her Lv. 2 and hope its stun Selene.