Too many maybes.
Get the codes checked.
Might even be that throttle position sensor you mentioned.
If the computer sees zero rpm it will give no shifting instruction to the transmission.
Plus the speed sensor possibilty. Zero speed sensed equals zero throttle response.
( in my 06 hyrbid Escape w/cvt, you can NOT rev the engine. Not in park , not in neutral. )
And with either of those conditions comes the possibility of wiring or plug problems creating the lack of signal.