5 years since breast lift - can I safely go from 550cc to 1050cc implants?

Since this is your fourth capsule and it is stage four, removing the implants and capsules will be your best solution. Otherwise, you need to go smaller and use mesh to completely cover the implants. Mesh is expensive and does not guarantee you will not develop another capsule.

Just changing the profile does not increase the volume. However, it does increase the forward projection of your breast and decreases some width. You may find changing the profile to a higher profile give a better look and may fit bras better as well. Choosing implants that are too large and...

Although you did not show photos, I suspect the problem is that your implants are much too large for your tissue and frame and your body will not support such heavy implants. There just may be no way that implants drops because you are stretched thinly now. You really need to consider going...

Adding about 75 cc's will give about a half cup increase in size, which will be noticeable. Your lower pocket can also be adjusted to let the implant settle down well.

You did not submit photos, so I cannot b specific. However, a fat transfer might work well. Please discuss this with your surgeon.

The empty bags are still present behind your breasts, but may be wadded up. There is no reason to be terrified because your body will treat them the same whether they are filled or empty. The ultrasound will show where they are. Sometimes you can feel the points of the empty bags.