My attempt at the answers:
i) 2 bond pairs and 2 lone pairs on oxygen atom therefore bond angle of slightly less than 109.5 degrees, around 104 degrees.
ii) 120 degrees bond angle therefore sp2 hybridisation.
iii) From what I understand, the sigma-pi separation means that you can neglect interactions between the Pz and Px,y orbitals?
The CH2 carbon would form SP2 hybrid orbitals.
The CH3 carbon would form SP3 hydrid orbitals and would then form 3 sigma bonds with the hydrogen leaving only one orbital to interact with the oxygen. I assume that the oxygen S orbitals do not match the energy level of the carbon and will form non-bonding orbitals. Therefore the C-O sigma bond would be SP3-P.
I am unsure how to use this knowledge to actually draw the MO diagram? I have tried an attempt below. I can draw MO diagrams for simple diatomic molecules. And how would the MO diagram explain the observed 120 degree bond angle?
iv) I haven't used the MO diagram to draw these resonance structures but I have come up with two based on the octet rule: