IMO, you are in good shape. Just keep your reported balances 9% or below. You can't do anything at all about the inquiries. They disappear usually within 2 yrs and FICO stops considering them by the 1 yr mark. Most lenders don't even care past 6 months.
I'd probably accept the offer if I needed a CC. You may want to snoop around over in the CC board to see if there's any possibility of a hard inquiry. I don't think it is likely. Make sure there is a lapse of at least 6 months in between the time you app for a home and the day the new Discover reports.