1. Yes, Alias: The Complete Fourth Season will release on October 25th. Cover art is available at TVShowsOnDVD.com.
2. No, they will not postpone season five until January. The current plan, according to J.J. Abrams, Jennifer Garner, and others closely linked to the show, say that the fifth season will involve, at least in part, Sydney training other agents to accommodate the pregnancy issue. January would not be feasible anyway, considering A) she can shoot episodes for the next few months and B) Jennifer will have the baby later in the year, and shooting after she delivers will mean that they will either shoot the episodes very quickly or the show will have a significant reduction in episode numbers.