I solod a necro here for a bit, just for the fun of it. They are quite powerful with the T8 pet when it comes to farming plat/aas. Like stated earlier, just take it one step at a time. If the others in your group can't take pulls of 6+ at a time, don't worry about it, just let the pet do everything till the others are caught up. PIVOTAL AA's for the necro: Pet hold and pet focus, followed by flurry. Every time you zone your necro, immediately /pet hold and /pet focus. Using this, you can make it engage, then send it to the next mob, so on and so forth, till you get a full room on it, and just watch it slaughter. You may need to toss in a heal every now and then, and the LDoN heal spell is pretty darn good at that. After a number of LDoN runs it becomes very mechanical, and the plat/aas just roll in.
As for later on, your pet can tank the *trash* mobs up to T6 with little difficulty, but any of the bosses t2+ will eat it for breakfast. Hope you enjoy your setup, necro is a very good contribution to any group with pet dps/group duration tap/group tap. Most of all, enjoy the server!

I find people who box ~3 toons have much more fun than those who run two full groups using their naughty macros. The setup you mentioned looks good. Your choice of ranger is a little odd, but they can work if well geared, and it's good to not be 100% cookie cutter every now and then.
Edit: and yes, slow is rarely used on THF. Though there are a few donor clickies with small unresistable slows that really help. Assuming no donor items, necro's Death Stalker spell make be enough to partially offset most early tier AEs, especially if it spams the t8 group lifetap in conjunction, shaman may very well be enough to keep you alive (dru/shm single target heals are almost as good as a clerics...)