Hakuna Matata

Paige & Locryn
They're in the same year so I'm guessing that they'd know each other, even if they'r not close? Locryn's a friendly guy and he's spent the vast majority of his life with people who've lost loved ones to violence, so he can be supportive if she'd ever want or need someone to talk to. Complicating that, however, are the rumours his stepbrother and GOH member has been spreading about his using the dark arts, so if she believes them there could be tension there as well?

Hayley & Murtagh
Could make for a fun interaction, considering that she's a muggleborn and he's a death eater? Murtagh's a very reluctant one though and he generally tries to avoid doing anything he doesn't have to, so... yeah. Possible shenanigans with Murtagh looking very fixedly in the other direction while Hayley sneaks off to her next safe house or maybe he distracts someone so she can get away from a dangerous situation at some point?
& Locryn
If she's ever hiding out around Bodmin Moor they could maybe meet? They're both Hufflepuffs (although a year apart, I think?) so they might have known each other from when she was in school and if she was in need and in the area it might be enough for Locryn to risk inviting her over to his mother's ancestral home. The original occupant really hated the living so it's a pretty secure place, just clearly home to several generations of necromancers.

Ariella & Murtagh
They might know each other as death eaters? Or if Ariella's still on the verge of considering it Murtagh might try to subtly talk her out of it. He'd get the family disapproval of it all anyway, overall his family's neutral in the conflict as they're far more about an independent wizarding Ireland and as far as they're concerned he's running around with the English oppressors. Most of them get that it's for a good reason, but still. Anyway, he'd probably like her well enough and want to try and help her if he could, even if it was just someone to talk to about the pros, cons and heartache of family.

Scarlet & Murtagh
Are both with the death eaters because of family, Murtagh only joined because the previous establishment wouldn't let him take his daughter home from st mungos after spell damage left her with epilepsy and the death eaters said they'd give her back if he helped them. These days it's always in the back of his mind that they might threaten her again to manipulate him and I'm guessing that Scarlet would have similar concerns for her brother, if she ever got him back, so maybe the two of them could consider teaming up to protect their loved ones and create escape routes/bolt holes?

Nadia & Murtagh
Could meet on Nadia's quest to find her father? Murtagh's got enough male relations to make his family/clan worth a look at least, and he's generally a good person so if she was ever in distress somewhere he'd try to help her out a bit. I think they could get on well, maybe, provided that his being a death eater stayed out of it? His daughter would like her anyway.