If you are going to style with the Octoberfest, than yes you need to lager it. Lagering is typically done by transferring it to a secondary fermenter.
You will indeed stir up sediment if you plan to bottle using the same bucket you lagered in. However, since you had already transferred the beer to a secondary, you've left behind cold break and a good amount of yeast in the primary. The sediment left in the secondary is usually just yeast that was in suspension when you transferred. So, you'll probably just end up with extra yeast in your bottles if you disturb that sediment while bottling. It might make it difficult to have a good pour from those bottles, but that is just a guess.
Another option...but its a PITA...is when you are ready to bottle. Rack the beer back into your primary, wash your bottle bucket and priming sugar then re-rack from your primary into your now clean and sanitized bottling bucket. That, or go buy a new secondary fermenter.