1Hill - My 2c
Yes, I believe core training benefits your cycling immensely - If done correctly
They stabilise the movements - in effect means that you use the muscles intended for moving quads, glutes, psoas etc) for moving and not for stabilising your body
Abs, erector spinae (deadlifts) does not contribute to the core muscles - only the core muscles like TA(transverse Abs), Multifidi and some obliques.
Ball exercises are way too advanced for almost all people who have not done extensive core training before.
Get to your local physio (sport trained) and start on a graded programme with slow progression.
