Regarding the bug when ordering Omni plant seeds, I don't think it's been fixed. However, there's a good work around for it.
1. Command your Sim to order the Omni seeds at the mailbox.
2. Cancel the action before it happens.
For some odd reason, this works and the new Omni seeds arrive the next day. Just be careful that your Sim is far enough away from the mailbox that he/she can't hit the dead end of the bug. If your Sim makes it to the mailbox, it won't work.