Nice
...and yes 2.5 gallons is too small... Roots is what you'll b eventually wantin to harvest so a pot or tub to allow lots of root space is what u want... Top trim n manipulate the plant with stress training such as bending over n tying down to force the plant to focus on strong roots n root production...I jus popped a few myself n ima have mine in 20 gallon tubs for each plant... I use 7 gallon smart pots for my Cannabis plants n they only live around 120days give or take n maybe 3ft tall n 3ft wide... The Mimosas will b growing some yrs before theyll b worth harvesting for roots...
Good luck w everything n they look healthy n happy so far... Looks ready n big enuf to transplant at any time now...I would go to a 10 gallon pot asap n then eventually upsize as it gets bigger with time...
✌