Below is the structure of alanine dipeptide. I have labelled just four of the carbon atoms (1-4 in blue). I need to identify (i) the hybridization state, and (ii) the number of electron withdrawing groups for each one.

I understand that nitrogen is highly electronegative and I read somewhere that double bonds tend to be electron withdrawing so my attempt is as follows:

1: sp3 with 1 electron withdrawing group
2: sp3 with 2 electron withdrawing groups
3: sp3 with 0 electron withdrawing groups
4: sp3 with 1 electron withdrawing group

Can anyone confirm that this is correct? I feel apprehensive about applying vague rules-of-thumb.