If you've had a fig tree for 3+ years and you've gotten no figs, something is wrong. I really don't mean to be critical, but I also don't want you to waste years failing to grow good figs if there's a problem that can be easily fixed.
Maybe it's your climate. But I'd also have to ask: Do the plants get good sun? Are they well watered, at least during peak growing season (April -July)? Are they reasonably well fertilized? And maybe most critically, are the pots big enough, e.g., 5g or bigger (though with good water and fertilizer even a small pot can perform well)?
For comparison, RI is not exactly heaven for figs, climate-wise. But as a rule here, a new cutting can grow to 3-4' (sometimes 6') in its 1st year and you have to pinch off figs so that the tree can concentrate on vegetative growth. I can't vouch for your varieties, but last year I got ripe figs off 1st year cuttings of a variety of Mt Etnas, Nero 600M, Emerald Strawberry, Fico Nera Duemane. This year my cuttings of Improved Celeste, started in December, are 2-3' high and wide; and I've been pulling baby figs off them for months. Even Black Madeira, started in late January, has tiny figs. So before you cull a variety, re-check the growing environment.
FWIW, your in-ground DK seems to be doing very well. So ask yourself why the potted varieties aren't doing as well. What's different? In particular, are the potted figs getting as much water and the in-ground fig?