Can anybody help me to identify where is leaking oil from?
The photo to the right with the belt to the pulley is your power steering pump... Twist the cap about a 1/4 turn and the cap should come up and there will be a dip stick attached with a gauge to check the oil levels.
While there are a few types of oil to run the power steering pump with different colors, chances are mercruiser power trim and steering fluid was used and could be within the color you are seeing mixed in with water...or you could use Dextron III automatic transmission fluid (ATF)
Genuine Mercury Hydraulic Fluid Trim / Steering Qt - 858075K01
www.iboats.com
The oil in the bucket is power trim fluid,
Or maybe your plastic power trim pump reservoir or fittings are leaking that run the stern drive up and down.
Time to clean and dry the bilge area under the engine really good and watch for oil leaks.
As for the bearing, if you can, 'try to pull the bearing out softly vs hammering it out if you're going to reuse it to help avoid potential damage.
Is that bearing a OEM Mercruiser bearing or aftermarket? What is the part number of it?
The housing where the u-joint bellows sits/mounts to appears either damaged/chipped out and some sort of epoxy applied. The new bellows may not seat correctly if that is the case. Come to think of it, it may have had an Bellows GHR kit installed or you may have to consider getting one yourself... GHR info here for you,
http://www.ghrkits.com/GHRKIT/ghrkit.html