Which coins will remain as the official currencies for goods etc. ? What do you think?
I'm a bit confused here??? Like you mean conventional currency? If that's what you mean, cryptocurrencies getting legalized doesn't mean that they are replacing any currency. They will still remain what they are which is crypto currency, and we are still going to have fiat which is the main currency we are using now and we still be using then.
Cryptocurrency being legalized means that there will not be any laws stopping you from making use of cryptocurrency, you will be free to make use of it if you wish to. But this means that it will be regulated and the government will likely to charge fees for it.