I don't think it is as bad as pgtips might make it sound. There are great lenses, there are bad lenses regardless of when they were made. While the A900 has a high total pixel count, due to the bigger sensor size it has a comparatively low pixel density so would be a bit more forgiving on sharpness than if you went for a lower range body.
When it comes to things like this, I often use the Alpha mount lens database
on Dyxum as a starting point, which contains user ratings for lenses.
The 24-50 and both 50mm lenses comes out well rated, all above 4 on a 5 point scale (some variations depending on specific model).
The Vivitar 28-200 does less well but still reasonably, but that's not too much of a concern as longer zooms don't tend to do as well.
One note of caution is that most user reviews will probably be using the lenses with a crop sensor body, making more of the lens' middle sweet spot. So border performance may be less good.
Look at it another way, what are the modern equivalents like? The exact version of the 50mm lens isn't stated, but if you take the f/1.4 as an example the Sony version is little more than the Minolta lens in a restyled body. Pretty much the same on the macro versions.
I guess the new questions are do you really need/want an A900 (or closely related A850)? What about the other models in the Sony range? Note they do have a smaller sensor so the field of view of the lenses will be different (smaller) in that case.
Alternatively if you don't use the film camera any more, sell the lot and start again with a clean sheet. Then anything goes - also opening up other brands.