@Skrodk

Thank you for using our software service.

Yes this approach is possible. Regarding the naming - one account would be one portfolio.
You can assign trade groups to each transaction e.g. Trade group "trading" and another one "HODL" to separate those transactions within the same account.
We have now an automatic depot separation for creating tax reports which helps as well.

We do accept just read-only API keys within while creating API jobs for exchanges as you would like to do.
Most exchanges do offer CSV exports as well which you can import in your CoinTracking account - either via direct CSV exchange import or the custom CSV or Excel import - if you do not want to use APIs.