I’ve seen somewhat similar hybrid deals, but yours will lure a lot of bad apples looking for an easy way to abuse programs 
. If you manage to get this out of the way, I believe affiliates will like it.
If I were you, I’d offer this promo only to affiliates you have worked with for like 6+ months. and disallow any new ones with sites with low traffic. Otherwise don’t be surprise if you see 100 UV/month traffics sites generate 300 unique sign ups .
A good question about the offer would be, how much would the rev share be afterwards, and will it be lower than say the industry minimum of 20%, because of the initial CPL bonus.