I was wondering if I could get some advice on the best way to tie a new foundation to an old one.

Here are the particular's of the job:
The prexisting foundation (60+ years) is concrete block, with the old wavy textured exterior.

Here are the questions:
1) Would a poured concrete basement addition be better to tie into the old one, or would a block basement be best?
2) What's the best way to physically tie these foundations together?
3) Is the old textured brick going to be a problem?
4) Is it possibly to 'share' the basement wall between the two basements, or would another one need to be built along side of it? (Which way is best?)

Thanks guys!