I think that the Catalonian government is prepared enough, if they should happen to win their bid for independence. We will never know for sure if they are totally prepared and ready, but the only way to find out is to just let them try it. Live and learn. They can learn from mistakes they make.
Yes, the government of Catalonia is prepared if they win their independence from the country of Spain. They have been separate for a long time, and have had plenty of time to find out what programs in their government work and also find the ones that are not any good.
I do not believe any government can be fully prepared for independence, but that's not to say they wouldn't be fine if they won their bid for independence. I believe Catalonia will be fine if it is granted its independence and rightfully, it should receive it, since they have requested it properly.
The Catalonian government will try to be prepared, but there will always be snafus regarding a new country being formed. Catalans have wanted independence since the 19th Century. Populist movements haven't completely gained a majority of Catalans just yet, but demonstrations happen near election time. The Catalonian government won't be fully prepared when and if the region becomes independent.
Catalonian independence has been a cause celebre in Spain for so long that it is now more habit than actual desire. The would-be government has been waiting in the wings for so long that they have become complacent. I think they would be shocked if they actually won independence, and would have no idea how to go about setting up and running a real government.