With the last boss a big NPC mob should take care of all the casters surrounding him and a little event happens. You should only have to face the boss and 2 adds.

He does a mortal strike on you and he 'swaps' places with one of his adds. Just DPS the one with low health. The adds aggro seems to reset once he swaps, so just pick up the other add again, they seemed to like my healer but wasn't an issue.

For the boss that you have to stand in the 'lava waterfall' only put him in it for about 4 or 5 seconds and start your AoE healing straight away as when he is in there he will do alot of AoE.

Dont stand on the grating and the big sploosh AoE fire wont hit you that shoots up out of the ground.

I used heroism and fire eles on most bosses because they are quite short.

For beauty the core hound, just kill all her adds before you start then tank and spank. She will put a debuff that cannot be dispelled on a target and charge them after a little while and knock them back a few yards. She will fear so have a tremor or fear ward etc.

I probably found the first boss the hardest as I wasn't use video strats at that stage just giving it a go. In throne of tides the fights are alot more complex (for a normal 5 man anyway) so I would watch the brief overviews that are on MMO-Champion when you click on each instance tyep for more detail. Overall very enjoyable - definetlyALOT of movement in all these instances so if you cant do movement get some practice.