You could do it if you ask me but you would probably need to have higher CP dps friends. CP imho are much more relevant when it comes to dealing damage than in roles as tank/healer.

Problem there are actually the mechanichs; you WILL want to understand them, in some point you WILL have to deal some DPS (daedric sacrifices level) and in the last boss you are probably going to tank him (or 2 subbosses depending on strategy used) yourself (tank will be busy with 2/4 other guys).

You could have some problem in lvl 8 when dealing sacrifice, take the right lane, there only scamps spawns so even if u fail to kill em it's not that bad; plus if u put the stronger DPS in the middle lane he can help u as soon as he's done.

More than CP the way u actually play can make the difference, the way your team work togheter can. If you really want to do that look for friends in some guild who are willing to do it, to waste some afternoon in there and who won't get mad or just blame u when they die only 'cause they see "low" CP.

I, as a tank, have done it 'round 450 the first time with a templar healer (same CP As me so 'round 450) and 2 DPS (both 720 tho). It took a while to get better as a team, to get all the mechs an so on (you can and will need to read guides/watch video but it's not the same experience that u'd get by seeing the real thing; watching, reading AND trying are complementary).

All of this could work provided your build is proper for PvE endgame content