Morning guys............
First... if you are reusing the drive shaft (that's not a prob) you will want to make sure that there are no rough spots to hurt the new seals and bearing.
The new seals will go into the seal carrier with the cup facing out. Remember... you aren't so much using the seal to hold the grease in... you are really trying to keep the water out. Also, since that rear seal isn't in the carrier... I'm going to assume that the old carrier is shot. (warn out) Did you check it yet? Or... did you buy a new carrier?
I've never used that "Water weld", so I can't give an opinion on it. But, generally... I don't like the putty type epoxies. As long as it's made by a reputable company... I'm sure you will be fine.
I got to run... but I'll check back later today.