A "trimac", flowerhorn and a 16" pleco is not going to work in a 110g for 9 months with a "very old person".
Get rid of one of the cichlids if you want a problem free environment.
Also, I seriously doubt a "very old person" is going to do 50% water changes on a 110g once a week which is what will be needed for this tank with those 3 fish.
You might want to seriously reconsider if you are putting all the responsibility of 2 psycho cichlids and a monstrous poop machine on a "very old person" for 9 months.
Get rid of one of the cichlids if you want a problem free environment.
Also, I seriously doubt a "very old person" is going to do 50% water changes on a 110g once a week which is what will be needed for this tank with those 3 fish.
You might want to seriously reconsider if you are putting all the responsibility of 2 psycho cichlids and a monstrous poop machine on a "very old person" for 9 months.
