Suarez and Costa calmed down a lot last year at least during the league, but both were angling for their big move and to big wages. Will either of them manage to contain the nasty side of their game now they have their contracts, who knows. We'll see.
The 2012/13 season was particularly nasty from both players.
While his goading of Coleman after he scored an own goal certainly wasn't sportsman like, he did it as he ran past, he didn't touch him afaik and didn't stand there for ages. It was just a **** you for barging me around a minute ago, nothing more. But I suspect he'll get a red or two this year and see if he does anything bad enough to get a longer ban, more than possible.
Costa did enough nasty stuff to get some long bans in La Liga but got away with all of it(beyond a standard red card) so the club may not have had any behaviour clauses in his contract. Suarez however you would imagine has all kinds of clauses, like not being paid for any week he has a ban, maybe losing out on title bonuses in any years he's gotten himself a 3+ game ban as well, that kind of thing. With him, no idea if it will help. Costa is youngish(supposedly at least) and may have grown out of it, Suarez is a repeat offender, way to old, i'd put money on him slipping up again in the future.