Can flowers be directly planted into a fresh cut cedar log?

Hi Debi and welcome to GoY. In short the answer is 'no' I am not aware of any growing plant that would want to be planted into a fresh cut cedar log but the ones you mention would not be happy. Cyclamen need damp shady conditions , ferns need even more damp and shady conditions - I don't know what Bocapa is but I don't think any plant it would be a happy bunny growing in a log!