Well, first - you can replace welrod. Her skill has no use here (even with decreased accuracy enemies will still be able to hit elphelt), and her rof buff is mostly wasted in MG's. You better use mk23, grizzly, contender or other HGs with damage buffing tiles and/or skills.
Second - don't stick to armor buffs so much. Elphelt has hella high armor on herself, and she does not need much more. Plus, she wouldn't need to take hits with her armored manly chest if enemies will be killed before they can reach her (smartNibba)! So you may freely replace mg4 with PK and live happily.
Formation should look kinda like that:
Pk |None |None
BAR |mk23 or whoever i have mentioned| elphelt
Mg5 | none | none
Hope I helped. Good luck my fellow commander.