susbtitiute for 1uf monolithic caps

Not enough information to be able to venture an opinion, I'm afraid. Your other choices in place of any kind of ceramic capacitor for that value, are an electrolytic, a tantalum type, or some other 'block' type, such as a polyprop film. The fact that a non-polarised block type has been specified, would suggest that characteristics that these types of capacitor exhibit, such as lack of polarity, and low leakage, are an important factor in the designer's choice. If you can tell us what the component's function is in the circuit you are constructing, we may be able to give you a better idea of whether a substitute type is feasible, and which would be the best candidate to not compromise the operation of the circuit.

Arfa