As long as you're not planning on breeding any of them I think they would be a nice addition. How many of each do you have already?
Sevs get big, just keep that in mind
From DJ/MC Decker
I dont think it would be a problem as long as youre not putting more than 1 or 2. Id stay with just one though. And id get rid of 2 of the CLs. They also get very large. Also, hatchets would be a good addition as well imo. What kind of filtration you run?
I keep both, just in different tanks. A group of discus would do well in your 70 gal w/ species you mentioned. Once a severum gets up to 10 inches or so, most of those fish could become a meal, maybe sooner. If you started w/ a very small sev you could be ok for a while though. My notatus have attitudes and my 7 inch one is keeping a festae aka red terror in check at the moment.
From DJ/MC Decker