Unleash is a good mechanic but there are creatures out there that are just as good as the unleash ones or better for about the same cost. I'll list a few below. Cackler being the exception probably, it's a pretty solid one drop.
Falkenrath is a superb card and should be main deck. If you like the black red stuff, then I would suggest looking into black/red zombies. A quick google search should come up with a few decks. Exava is an okay replacement for falkenrath but in the format falkenrath is the better card. The zombies deck doesn't even really care if she sacked a human it's more about the interaction with gravecrawler and keeping her on the field.
If you just want to do a regular aggro deck splashing black then you'll need more 1 drops. Cackler is good, you'll need stromkirk nobles, diregraph ghoul is okay too. Spike jester is a great 2 drop fro BR ash zealot is great too. Alternately you can use burning tree emmissary and lightning mauler, doesn't match up as well with zealot and spike jester. For 3 drops you could even use boros reckoner even though he's 3 red in the deck. You can run falkenrath or hellrider.
Remember aggro decks are like pyramids. One drops make your base then 2 drops then 3, then a very few 4 drops, and depending on the deck a couple 5 drops like thundermaw helkite. Alternately the 5 drops can be 1 2 or 3 drops. The strategy is to increase the likely hood you'll have a turn 1 play and subsequent plays on the following turns. Below is the layout for a 30 creature aggro deck. That gives you about 8 cards worth of spells/removal and 22 lands.
55
4444
333333
22222222
1111111111
Consider this
Spike jester = Shredfreak
Ash Zealot = Chainwalker, 2/2 with first strike haste and a useful ability against decks that cast from the graveyard.
Boros Reckoner = splaterthug (3/3 for 3 without unleash and it can have first strike and it gets a damage redirect ability, much better than splater thug).
Falkenrath = exava (flying to get accross, haste, can sack to be indestructible and/or add counters, much more damage potential than exava)
Hellrider (haste, 3/3 makes all your attackers do extra damage)
Some cards to consider removing.
Dark Favor, if they remove the creature you put it on then you lose the enchant and the creature so your investment in the enchant went for nothing. We call this a 2-for-1.
Cryptborn horror, the other 3 drops are just better. Hellhole flailer is a consistent 4/3 with a good ability and doesn't require a conditional circumstance like the horror. Really a reckoner would be better here, but I know they do cost $$.
Rakdos charm, just bad here. It's not going to help you enough to include in the deck let alone 4. You're much better off just adding more dudes.
Shred Freak, for the cost and colors spike jester is just better. Get some of those to put in its place.
I might post or message you with the final deck if you don't mind giving it a look over? 
But thanks a lot no matter what! You are a real bro!