Ross,

You can make it a lot easier for future events, the dust cover nearest the key can have a small close fitting cutout filed into it, that will allow the shaft to come out with the key still in position. As long as you keep the cutout at the top when you fit the cover into the casting, it will still do it's job of retaining oil in the bearing for as long as possible.

That would also help in getting the outer dust cover off, as the key would push on the inner bearing race and knock the outer cover out when it moves the bearing.

If the bearings have been pre-loaded for any length of time without being run, you will find they may have 'brinelled', they feel ratchety, and as such are of no further use.
The Atlas bearings have a specially shaped outer race and as far as I know, are special order only from Clausing (the genuine US Atlas spares company) themselves, and worthy of a second mortgage.
The inner race is a standard Timken part. I had a friend regrind the inner faces of the old outer races, and then I fitted new Timken inners. That came to a fraction of the cost of new bearings all round. I now have my own facilities to do that sort of regrind if you need it.

John