You can certainly try and in most cases i've seen does work out ok, Like Oscars, Frontosa seem to be quite intelligent and not overly aggressive and IMO a good tankmate provided you aren't aiming for any kind of biotope
im not aiming for a biotope of any kind just a nice selection of fish that i would not normally be able to keep. ive been and got 2 sun catfish today as my bottom feeders so thats threw any biotope out of the window
ive come up with a list for stocking that seems to be ok, it is -
2 x sun catfish (already got 2 small ones)
1 x oscar
1 x red spotted severum
1 x texas cichlid
1 x large pleco
6 x silverdollars (not 100% on these yet)
and now if the frontosa is suitable thats gone and messed it all up again
maybe swap the silverdollars for the frontosa or is that too many big cichlids in this tank?