Knowing how Hasbro deal with "new" Star Wars figures they are more likely to use an existing mould and repaint/rebash that then create a new mould entirely.
Flint and Ripcord would work with Skip (or mayby using Stalkers body and Flints head) and for Eagle you could use the Snake Eyes V1 body (i.e SAS Stalker) though the head could be difficult as i don't think any Joe has a removable gas mask.
For Leviathan they could repaint the new EEL figure
http://www.hisstank.com/gi-joe-news/att ... entid=1684
Not sure on Space Commander i'm afraid, i'm sure there must be one figure out there which Hasbro could repaint!