Yup you should be just fine, ZCO 4.5.x will work against ZCS 5.0.x just without the 5.0 features.
There's backwards compatibility because you can't immediately upgrade your server & an entire fleet of outlook users at the exact same time.
The idea is to use the connector version that's as close to your server version as possible for any server side changes that might affect things - and 5.0 has a few!
After your server upgrade to 5.0.1 you should distribute the newest connector - as you already plan to do that is
