Since there are no upgrades anymore for VCS, you have to "switch" them to Expressways. But IIRC, Expressway doesn't have all that features, which VCS has. So you should check the Docs, which features you need and which features Expressway supports.
For licenses: Which lics you need to have in the Smart Account depends on your needs. If you have B2B calling, you need RMS lics. If you have devices registered, you need device registration lics, etc.
Nobody in the forum knows your setup, so nobody can give you a definitive answer.