There are characteristic chord progressions taught in music theory, for example, the cadential 6-4, which is Ic - V - I. Then there's Ib - ii7b - V - I, & so on. I want to know if these cadences have to be written as is, or they can be modified by writing one or more chords in them in an inversion?
Also, from a previous question asked by me (double the third or the fifth of a chord), I learnt that notes other than the root are also doubled. I want to know if this is ok to do in the cadences I mentioned above (& other examples of such characteristic cadences). For example, is it ok to double the third instead of the root in chord Ib of the Ib - ii7b - V - I progression?