Your Team is very very Very offensives, the walls you have will do nothing and the movesets dont have the vaavaa voom. I love how its a dark team, but we can get through this...
Umbreon, really? Adamant? then use a special attack like shadowball? Adamant will lower your special attack,you will get more damage by throwing a loaf of bred at your apposition.
Either go for Relaxed or Sassy depending on how you want your defence. Trade shadowball for a sexy payback, since that is one of the strongest dark move umbreon can learn when it goes second. Toss out attract cause that is more useful than Marmalade. Put in either a toxic or a curse, and stall biatches tell they die.. If you want you can trade your moonlight for Wish as it can help heal your team members aswell...
Drapion will sadly will be walled by the scary thought of Steel types, expecially Heatran, so cut out either Arial Ace or Cross poison, and give him a cheaky Earthquake. And REAAAAAAAALY? Impish? god put in a jolly or adamant, or get rid of toxic put in Earthquake and fire away with the choice scarf.
I see what you are trying to do, get a bulky tyranitar, but if its gonna be mid way sweepertar, you need to give him Dragon Dance and max our speed/attack, so jolly or adamant respectably, giving some evs to defence. And not one but TWO rock moves? thats like makeing a good sandwhich and putting two differnt types of Cheese that dont taste well together. So pick one. and arial ace/ Crunch doesnt really matter with DD support.
Weavile = decent i suppose
Your houndoom makes me wanna cry till I die, Lonely? SERIOUSSLY LONELY! lonely = +attack -Defence, serioussly *cuts wrists* you give him attack benefiting nature and then throw in a bunch of special attacks? give him a modest or timid and ride on to victory! except Solar beam= Dark pulse, sunny day= Nasty plot.... maybe give him a cheaky focus sash?
Spritiomb :O Its not bad, but calmmind, might be better than nasty plot and hypnosis consider willowisp but not too important... but if you go for willowisp cut some of the Defencive evs and give it to Hp