In situations where you have a face with very strong personality, the best approach for a companion face is to go to the opposite extreme: a plain sans that isn't trying to assert itself. Kursivschrift has relatively narrow proportions with a severely vertical axis and no slope, so that it almost looks like it's leaning backwards. Its x-height is large.
Your tagline/heading face will work best if it is also on the narrow side and also has a vertical stress and a large x-height. Kursivschrift is quite dark, so your tagline font must be light. (In a tagline, you're not trying for a match; you want a contrast.)
URW Grotesk is drawn a little wider than Kursivschrift and has a lower x-height, so to my eyes it collides, rather than contrasts or harmonizes, and the bold is certainly much too dark to use for the tagline.
When you know there will be many items to typeset but you don't know what they will all be, my advice is to pick OpenType families for both headings and text that provide a good selection of weights and preferably have condensed and/or extended forms.
In this particular case I would go with Myriad or (if you need to be very conservative) Helvetica Neue Thin Condensed for the companion sans. Myriad has a wide range of styles, and the Helvetica Neue family is massive.
The obvious pairing for Myriad is Minion, but Arno (also by Robert Slimbach) is a more recent and less-used face that is also available in light, regular, semibold and bold weights. Both are very readable and will pair equally well with the narrower Helvetica Neue fonts. Importantly, both families now have optical sets, drawn explicitly for each of caption, text, subhead and display sizes.
If you've not experienced setting serif type using size-specific fonts, I highly recommend it. You may find that you have less need of a sans for your headings and subheads when your serif face has fonts drawn explicitly for those sizes (and don't, therefore, look clunky).
