That sounds rather like a way to skirt the whole "No putting ritual spells into enchanted items" thing, which I had not considered
Definitely a clever thing, the ritual spell container; A storyguide might state that containing a Ritual spell requires a Ritual spell, though it's not stated so it's really just a storyguide call. I also don't think you can decide the target of the spell when it's released, doesn't it have to be declared when it is first cast?
even if you do if you are saving this for personal use it isn't a problem.
Yes, you could, but remember that we're talking about young magi wanting to preserve their fertility, and now they have to not only be good at CrCo, but also ReVi, in basically equal measures because the two spells (Aging Crisis and 'Container') will have to be roughly the same level and probably both are ritual spells - Watching Ward being a ritual to support its indefinite duration.
Now, it's entirely possible for a magus to do this, but it really narrows down who can do this. Not a lot of magi have around 10 in those 4 arts in addition to whatever they're specialized in at the age of 35 (I'm assuming you'd go for the level 30 spells in both cases). Specialists in 2/4 arts involved will have no problems aside from the year long investment of learning and mastering 2 ritual spells and the 12 pawns of vis being used, which is a pretty big investment before age 35 on basically a contingency plan.
Of course, there could always be the aforementioned specialists who sell these spell bottles, but given that the level 30 version costs 12 pawns of vis to make, the selling point is probably going to be well above that value.
Entirely possible to do, but putting more effort into avoiding the Crisis in the first place is probably a better allocation of resources - bronze cord score, healthy laboratory, dietary consultant, etcetera.
Or purchase the bottle from a verditius...