If anyone is worried about corrosion: Galvanic corrosion will occur if aluminium is in direct contact with the carbon fibres however it is so slow that it is measured in a time scale of decades so not a big deal unless your doing it in a production aircraft.

Some searching got me the answers needed about this. I'll stay away from alu honeycomb for now, because making an outer and an inner skin beforehand just won't be possible in this case. Closed cell foam will be used instead, making a "skeleton" core structure between layers in high stress areas.

Hi again!

I am not sure about wet lay up, but for infusion it would be impossible. Are you not planning to use resin infusion? If you wish to include a core in resin infusion you should have a look at Lantor Soric. 

The way I interpreted Matt's answer in the linked-to thread it seems the alu honeycomb is to be bonded onto an already cured outer shell of cf, and then the inner/next layer is to be bonded onto the honeycomb? I am planning my layup as a one moment all wet process, i.e. everything is to be laid up on the one same occasion. Would alu 'comb be unsuitable for this?

I have never bonded honeycomb to CF panels personally, but it works. There is a special adhesive to bond the core to the panels. Theres a thread on it here: 

Hi!