The thing about album credits is the hip-hop community is so out of touch for what can get you writing credit. Writing credit is not just a lyrical contribution, it's also anything musical. There are a bazillion ways to get writing credit.
- You contribute a hook or reference
- An A&R (or simply a connection) gets a beat from someone and that someone has done some work on top of the beat that influences the record
- The beatmaker himself
- Your homie lets you know that line was wack and that maybe it should go like this (everyone does this and there's zero problem with this IMO, only way people get better)
- Samples, including ones they record themselves and chop up
- The-Dream adding the -ella-ella- to Umbrella
It's a losing game to try and figure out, but if Meek does claim he heard the reference track with a completed verse on it it's cause for controversy. It's all hearsay until keeping it real goes wrong (or right).