Ting doesn't have any problems activating BYO(S)D, and depending on your T-Mobile coverage and given your husband's usage on Airvoice, it might be worth considering a switch if you're wanting a bit of flexibility with heavier usage and if you want to manage both phones under the same account despite being on both CDMA and GSM.
That said, there's cheaper for both of you at the levels you're speaking about than Airvoice's $10/month plan and Ecomobile, and that goes for Ting, too.
At the levels you're talking about for your husband, it might be better to straight up switch to Airvoice's PAYGO, H2O Wireless PAYGO, or even Puretalk USA's Simple 80 plan (all AT&T) or P'tel Real PayGo (T-Mobile), all of which should get him down to at least $5/month or lower. As for yourself if you're expecting similar usage, look into RingPlus and something like their newer Joy plan. I'm not completely over the moon about some of RingPlus' legal agreements (mostly the privacy stuff, and it is a bit less invasive than FreedomPop), but I've also seen far worse legal agreements in general in the MVNO industry than theirs. There's also Kajeet on the Sprint end, but RingPlus is cheaper. With a little re-arrangement, the two of you could probably get both lines for less than what you're spending now just for him.