Is cannon law the same for all Eastern Catholic churches or would be different say between Maronite, Ukrainian, and Coptic Catholic?
The CCEO applies to all.
Each may also have particular law as a sui iuris church.
Those churches with multiple eparchies/dioceses may have diocesan particular law, as well, but few do so.
Canon Law is inherently different within the various Eastern Catholic churches. The CCEO (Code of Canons of the Eastern Churches) is a framework that describes the external relationship between the Pope and Eastern Churches, as well as other laws that all Eastern Churches have in common. However, the CCEO covers only a fraction of Eastern Canon Law, and does not replace the particular laws of each Church. For most aspects of internal governance and laws, each Church still has their own unique Code of laws, in very much the same way that the Latin Church has their 1983 Code of Canon Law.
To put it very loosely, think of the CCEO as like an EU law that describes regulation common to all EU states as well as relationships between the EU states and the coordinating European Commission, but each state still has a vast body of legislation that makes up the bulk of law within the state. A major difference is that the CCEO is not meant to replace or override the particular laws of the Churches, whereas EU law can do so to their member states.
Can particular canons from synods convened whilst in schism (Persian Ctesiphon councils or the Palamite councils) make up particular law of each church? Can those supersede the CCEO?
Provision for Particular Law exists in the CCEO.
What does this mean?
Every Church Sui Iuris and every eparchy and metropolia is allowed to have it’s own body of Canon law applicable only to its own constituents. Such bodies of law are called Particular Law.
For example, the canon law affecting the Eparchy of Phoenix is all the canons of the Ecumenical Councils, the CCEO, the Ruthenian Particular Law of the Metropolia of Pittsburgh. It could have its own particular Eparchial Law, but as yet, I’ve not heard of any in the form of law. There may be some other bits from various bodies in Rome that apply in specific cases, too.
Here is an example: