iserith
Magic Wordsmith
I have no interest in psionics and only allow them in Dark Sun games, so I have not familiarized myself with the Mystic class.
I feel the same way about psionics, but at least I'll get to comment on any Mystic threads once I see her in action.
Devotion Paladin and Necromancer Wizard can easily result in intra-party conflict if played conventionally.
Maybe it's the pessimist in me, but all I see is infighting: racial and professional. The elf doesn't like the dwarf, and the human sees the half-elves as half-breeds. Then the rogue of three levels is intimidated by the bard of six levels, the wizard makes the other magicians feel inferior, and the paladin wants to knock all their heads in for being less than perfect. But that's only if they're decent role-players.
They are decent roleplayers, but intraparty conflict is not a concern.
Make sure you're keeping the game balanced around 6-8 encounters per long rest, or your lock/rogue is going to feel very weak compared to the rest of the group. You mentioned overland travel, which is what usually triggers the issue in the first place (one or more days pass between encounters).
Good point. The pace will be set by the PCs, but like all my games, the countdown timer is in effect - manage your time poorly and you will suffer for it. Overland travel will be either at the 1 mile or 10 mile scale depending on the situation.