1. Who’s your target market?
Your target market and attraction mix (a coaster and a ferris wheel?) will determine the best choice. Both are good choices.
1a. If it’s a mix entertainment venue, like you’ve stated, what’s that mix?
If you have more family oriented venues, stick with family (i.e. wood coaster). If you plan to expand the mix and if family is decently covered, go with a thrill (i.e. inverted coaster). If it’s a -would be- teen hangout like malls, movies, etc., it would really depend on your long term goals. Most will only ride one available coaster a limited number of times.
Remember, noise. Will there be neighbors (i.e. NIMBY) prior to development? A wood coaster may be out and the non-dampened B&M roar even more so. There's additional cost to quiet them.
2. You’re very focused on GCI and B&M. You said you haven’t contacted them yet. Will they and can they make the product you seek in your project timeline?
3. What’s your projected attendance and do those numbers support a $15 million attraction?
4. If you can invest up to $15 million in one attraction, could you split the difference and gain two solid attractions instead of one? Perhaps a solid wood coaster with a couple of thrilling flat rides?
These questions aren’t meant to be answered here. Just possibly helping you go deeper to find the right answer to this question along with the responses you receive. You may already know these things.
My answer:
A steel mega-lite or hyper by Intamin. I know that isn’t a given option, but it’s the best of both your options. It meets all criteria. Any dueling coaster wouldn’t be the best for your initial resources.