All meta-psionic feats (and several other feats) require the expenditure of the manifester's psionic focus. Apart from one feat (Psicrystal Containment), it seems like a manifester may only hold one psionic focus at one moment in time. Thus, is there any way to apply multiple meta-psionic feats to one manifested power (such as an Enlarged, Extended Astral Construct with a Talented Overchannel)? Can a manifester even apply two psionic focus expenditures (his/her own plus the psicrystal's when using Psicrystal Containment) on a single manifestation?
The most powerful way to bypass the Focus expenditure requirement on metapsionic feats is playing an Ardent and using the Dominant Ideal ACF. A Dominant Ideal Ardent does not need to expend their Focus when applying metapsionic feats to their chosen mantle.
Another way is to play an Elan and take the Elan Retainment feat (from Complete Psionic), allowing you to not lose your psionic focus once per day when you otherwise would.
A third, but mostly inaccessible way is Epic Psionic Focus, allowing you to power two feats with the expenditure of one focus.
And you have already discovered Psicrystal Containment, the most accessible way by far.
As for whether it's possible to use two metapsionic feats at once - yes, it's generally assumed you can combine the uses of two or more feats, as long as there are no action incompatibilities. Also, for what it's worth, the FAQ seems to agree (page 93):
I have a question about psionic focuses. Psicrystal containment allows you to use your psicrystal’s focus instead of your own, and Epic Psionic Focus allows you to use the same psionic focus to power two psionic feats. What isn’t covered is whether you can expend two psionic focuses at the same time. Can you use both your own personal focus and the psicrystal’s focus in the same round? For example, could you use your personal focus for Deep Impact and your psicrystal’s focus for Psionic Weapon on the same attack?
You can use them simultaneously if you are doing different things with the expended focus, but if you are using two foci simultaneously to amp damage on the same weapon, it probably doesn’t work—unless the DM feels there is a good reason to allow the combo. I could certainly see this being allowed in some cases.