Other than the dual-layer thing (and only that because Sony put up a sticky about it), I never even heard of any of those bugs. You mean there are actually people reporting bugs through tech support without ranting about them here? How dare they! ;-)
No. DVD Architect and DVD Architect Studio are 2 different products. You can't just upgrade DVDAS to DVDA, you'll also need to upgrade from VMS to Vegas (since DVDA is only sold with Vegas, just like DVDAS is only sold with VMS).