Its worth pointing out that if we use an alignment on which in both the Cha and the Rumba there are none. Imagine we are in the middle of the floor both facing each other and are dead square with the dance floor. A Spot Turn in the Rumba. We are not bound to step down the LOD if we dont wish to. If we like we can step towards each corner of the floor on a diagnal. A New York the same. With the Spot Turn we will turn over the foot of which the whole of the foot is in contact with the floor, that includes the heel. That step is in the manuel as Ball Flat. We do not turn into the step. We turn at the end on the count of ( and ). Which is Three and. At this stage if we wished to change we could either walk backwards or forward . Wally Laird in his book calls it a Forward Walk Turning. The New York is a Checked Forward Walk. On the Spot Turn to the Right in the description which is LF fwd across body turning to finish LF back and slightly to the side. That does not mean that the LF moves from the spot. It simply means that if the first step is not taken across the body you would finish with your feet crossed up and your LF would be behind yourself. Now that isn't hard to understand is it. Just do as the book says.

"is step 3 of a spot turn in cha-cha (ie step 1 of the chasse) a fwd walk tng?"

No, it's not.

Laird uses a fwd walk turning for the equivalent step in Rumba. This fits with his description of a spot turn as three fwd walks (two walks and chasse for CC). Most dancers nowadays prefer the sharper action of the alternative step & replace spot turn which tends to make the third step a side step even in Rumba.

The speed of the cha cha, together with the split beat and the chasse action, make it virtually impossible to dance a fwd walk turning on step 3 even if you wanted to. It is pretty universally danced as a side chasse with any residual turn being made on the standing foot as step 3 is taken.