It's possible for fat to grow without weight gain. Fat cells often expand as you get older and fat cells are susceptible to hormonal changes.
Another cause of 'growth' is scar tissue development. As some of those articles have shown, chronic inflammation can bulk up the surrounding area too. This inflammation can also be 'low level' inflammation i.e. when it isn't a granuloma or infection.
By the way, the fat goes sloppy after a while. After about a year or so, it just looks a mess - like sludge. As the stuff sticks to the skin and muscles like glue, it contorts your facial expressions and makes your face look droopy in an archetypal 'plastic surgery' way. Fillers don't look as awful, simply because they don't 'ingrow' into your actual tissue. It's stupefying how PSs will say that this is what makes the fat grafting 'better' than fillers, when they cite this exact same thing as the root cause of aesthetic ugliness after other so-called 'permanent fillers'.
The people who *might* be happy with fat in the long term would have to be so aged - to the extent that they'd be prepared to overlook all of the horrible side effects.
About Saboeira - I'd assume she'd be doing more or less the same as Coleman. If the fat grew after they saw him, then that basically proves that even someone like him can't actually predict a good long-term result.