Hi,
I did this tour in March - albeit with Travelsphere but it is the same route.
As Julia says there are no "hikes" but in the towns, then after years of embargo, you will find a few gaps where paving stones used to be but in all towns everything is fairly well on the level.
Away from towns then the two main walks we had (optional) were the botanical gardens which again are fairly level and at Los Jasmines there was the opportunity for a morning walk in the Vinales valley. An incline down & back but nothing anyone with average fitness & mobility could do. Well worth doing in my opinion.
Sensible footwear such as trainers would be more than sufficient.
Ian