The 25% business portion can qualify for the business credit on Form 3468. But it is more complicated than the personal/residential credit.
Yes, it is five years. I remember the categories, but there probably is one that gives you five years. If you can't find it, yes, you can do the "other" and select 5 years, 200%DB. However, HALF of the business credit will reduce the Basis, so you'll need to partially reduce the Basis for depreciation.
