You've posted your question in the community for the Mac version of Numbers, and made no mention of iOS or iPad in your profile information displayed below your original post.
Is there a My Templates section in the Template Chooser on the iPad? If so, you can modify the tempates you want to use to contain only 'sensible' colours, then save the result as a Template. Templates you create and save appear in the My Templates section of the Template Choser.
You should be able to make or revise those templates on the Mac or on the Pad, then transfer it to the other.
All theoretical from my point of view, as I don't use iOS. You'll have a better chance of receiving an iOS answer from the users in the iWork for iOS community. I'll request this discussion be transfered there.
The text is cmyk process colors and it seems your printer is not doing a great job of translating those.
True Apple should not have been so sloppy in creating their templates. You can fix it by changing the text to strict black only in the Color Picker grey scale selector and making it part of styles to apply overall but it is hard to get every instance and correct it as there is no visual clue onscreen.
You could try giving Apple feedback but all mine has fallen on deaf ears.
Maybe, just maybe, Apple will do something about it in the new upcoming version but given past experience I wouldn't count on it.