Need some advice on mixing tangs

hi folks,

i have a 67 gallon tank keeping a mix of malawi, victorian and tangs

the stock list as below:
1) 3 yellow lab mbuna
2) 3 P.acei mbuna
3) 1 rusty mbuna
4) 3 Manigano mbuna
5) 1 electric blue hap
6) 3 P.neyerri (victorian hap)
7) 1 N.bichardi (tangs)
8) 1 sydonotis catifish
9) 1 small tiretrack eel

i always wanted to add more tangs but as i know tangs are harder to keep
and they are expensive investments.

therefore i need your advice to add some tangs which are tougher and easier to keep which will work in a mixed tank

some tangs i have in mind:

1) Black Clavus
2) Callochromis macrops or Callochromis pleurospilus
3) Julidochromis marlieri
4) Neolamprologus sexfasciatus

but it is hard to choose. please advice me

thanks!