Can all this be done in 1 day...?

[weakestlink]

Is this too much for 1 carpenter in 1 day?

Hang 2 1"3 doors
Hang 1 2"6 bi-fold door
(doors are softwood so not heavy)

Cut and fit 1500mm solid oak worktop

Cut (length only width is as required) pine 15 shelves and put up.

if you mean 15 shelves then yes, it looks like quite a lot in one day.

Yes fifteen small shelves inside a cupboard...

2 days then?

Yes - but not knowing how complex shelves and worktop are you may want to allow half day contingency.