I would like to disable aging for some families but not others. I would also like to manually age up whatever sims I want. What's the best mod or combination of mosd for this?

Either Monique's Individual Aging or BoilingOil's Slow Aging Controller (note you'll probably want to edit the default BCON settings) can let you toggle aging on specific sims.

The Aging off cheat works on a household, so it only applies in in households where you have entered "Aging off" in the cheat bar in the household's lot. So I reckon that the Aging off cheat is the best way to disable aging for specific families. Myself I actually try to keep aging normally off in all my families, but when I add a new family in CAS, or Sims move out and start their own household, aging is on in that new family until I remember to enter the "Aging off" cheat on their lot. Personally I prefer to temporarily turn aging on again to let Sims age up (that way they get to have a birthday party! ), but I can also use the Sim Manipulator to age Sims up. More often I use it to adjust Sims' Days left, so only the intended Sims age up after I turn aging on.

Monique's mod lets you turn Aging off or on for individual Sims within the family, but, as you want aging for the whole family to be either off or on, I think the Aging off cheat will be better for you.

If you ever need to age an adult down to a teen or a child, it is better to use the Sim Manipulator than the AgeSimsCheat, as the latter sets their school grade to F, which will cause the Social Worker to take the children, or the teen t o lose their job. The Sim Manipulator sets their grade to C.

Neither of these seem to work with pets, though. (Okay Monique's does, but it requires a clock which may or may not fit your house). Ideally I'd like to find a mod that works with pets and doesn't require a conspicuous object.