Help me with my Halloween decoration

Java, 829, 798

Yeah. Substantially improved thanks to Kevin Cruijssen and corvus_192.

s->{String[]e=s.split(" ");char c[][]=new char[8][e.length*6],t,u,h='|';int y,x=2,i=0,j;for(String l:e){y=0;char[]p=l.toCharArray(),z=c[y];int a=p[0],b=p[1],f=p[2],d=p[3],k=x-1,m=x+1;t=a<49?'°':a<50?'¯':a<51?45:a<52?'^':39;u=(char)(b<50?b+70:b<51?111:b<52?95:39);if(d>50){z[x]=h;if(f!=49){y=2;c[1][x]=h;c[2][x]=h;}z=c[y];z[k]=46;z[m]=46;z=c[++y];z[k]=58;z[m]=58;z[x]=34;}if(d==50){z[x]=40;z[m]=41;c[++y][x]='´';c[y][m]=96;}if(d==49){z=c[++y];z[k]=94;z[x]=34;z[m]=94;}if(f>49){y=6;c[y][x]=44;}if(f>48){y=f>49?7:3;z=c[y++];z[x]=u;z[k]=t;z[m]=t;z[x-2]=40;z[x+2]=41;}if(f==49){z=c[y++];z[x]=h;z[k]=95;z[m]=95;z=c[y];z[x]=h;z[k]=91;z[m]=93;z[x-2]=47;c[y++][x+2]=92;c[y++][x]=h;c[y][k]=47;c[y][m]=92;}x+=6;}for(;i<8;i++){s="";for(j=0;j<c[0].length;){t=c[i][j++];s+=t<1?' ':t;}System.out.println(s);}};
    

the ungolfed version

static void makeDecorations(String s){
    String[]e=s.split(" ");
    char c[][]=new char[8][e.length*6],t,u,h='|';
    int x=2,i=0,j,y;
    for(String l:e){
        y=0;
        char[]p=l.toCharArray(), z=c[y];
        int a=p[0],b=p[1],f=p[2],d=p[3],k=x-1,m=x+1;
        t=a<49?'°':a<50?'¯':a<51?45:a<52?'^':39;
        u=(char)(b<50?b+70:b<51?111:b<52?95:39);
        if(d>50){z[x]=h;
            if(f!=49){y=2;
                c[1][x]=h;
                c[2][x]=h;
            }
            z=c[y];
            z[k]=46;
            z[m]=46;
            z=c[++y];
            z[k]=58;
            z[m]=58;
            z[x]=34;
        }
        if(d==50){
            z[x]=40;
            z[m]=41;
            c[++y][x]='´';
            c[y][m]=96;
        }
            
        if(d==49){
            z=c[++y];
            z[k]=94;
            z[x]=34;
            z[m]=94;}
        if(f>49){
            y=6;
            c[y][x]=44;
        }
        if(f>48){
            y=f>49?7:3;
            z=c[y++];
            z[x]=u;
            z[k]=t;
            z[m]=t;
            z[x-2]=40;
            z[x+2]=41;
        }
        if(f==49){
            z=c[y++];
            z[x]=h;
            z[k]=95;
            z[m]=95;
            z=c[y];
            z[x]=h;
            z[k]=91;
            z[m]=93;
            z[x-2]=47;
            c[y++][x+2]=92;
            c[y++][x]=h;
            c[y][k]=47;
            c[y][m]=92;
        }
        x+=6;
    }
    for(;i<8;i++){
        s="";
        for(j=0;j<c[0].length;){
            t=c[i][j++];s+=t<1?32:t;
        }
        System.out.println(s);
    }
}

Favorite decoration (which apparently looks more evil in my console): terminator skeleton

(-w-) 
 _|_  
/[|]\ 
  |   
 / \

JavaScript (ES6), 319 315 bytes

let f =

s=>[0,1].map(i=>s.map(([A,B,C,D],x)=>+(z=i?D:C)&&[...'01/21/5015/41211/91/65'.split`/`[z-(i?C+D-13?1:-2:-2)]].map((n,y)=>a[(i?y:6-y)*4+x]=' '+('      ^"^   ()   ´`  / \\   |   .|. /[|]\\ _|_ ('+(e='°¯-^'[A])+'vwo_-'[B]+e+')  ,   :": ').substr(p+=n*5,5),p=0)),a=Array(28).fill`      `)&&a.join``.match(/.{24}/g).join`
`

console.log(f(["3123","0002","1021","0310"]));


Ruby 2.3.1, 777 752 bytes

Edit_0: I totally missed out on some golfable variable usage and some other stuff.

@o=Array.new;$*.each_with_index do|j,i|a,e,n,b,u,q,r,z,y=0,j[0].to_i,j[1].to_i,j[2].to_i,j[3].to_i,['°','¯','-','^',"'"],['v','w','o','_',"-"],Array.new(7," "),"     ";g,h=[z,["(#{q[e]}#{r[n]}#{q[e]})","​ _|_ ​","/[|]\\","​  | ​ ​","​ / \\ ​"],["     ","​  ,  ","(#{q[e]}#{r[n]}#{q[e]})"]],[z,["​     ​","​ ^\"^ ​"],["​ ​ () ", "​ ​ ´` "],["​ .|. ​","​ :\": ​"]];2.times{h[3].unshift("  |  ​")}unless b==1;if b<1 && u<1;@o.push(z);elsif b<1;u<3 ? (a=5):(a=3);a.times{h[u].push(y)};@o.push(h[u]);elsif u<1;b==1 ? (a=2):(a=4);a.times{g[b].unshift(y)};@o.push(g[b]);elsif u>0;2.times{h[u].push(y)}if u<3&&b>1;@o.push(h[u]+g[b]);end;@o.push(z);end;@o.transpose.each do|v|;v.each do |w|;print w;end;print"\n";end

Takes in N number of variables of decorations. There's certainly some more golfing that can be done with this. I'm not that familiar with a lot of Ruby's tricks, but here's a shot at it! I'm also happy at being able to solve it.

Un-golfed

@output = Array.new
$*.each_with_index do |j, i|
  # output decoration combo
  s = 0

  # set up vars for decoration input
  e = j[0].to_i
  n = j[1].to_i
  b = j[2].to_i
  u = j[3].to_i

  # Setup decorations/misc
  eyes = ['°','¯','-','^',"'"]
  nose = ['v','w','o','_',"-"]
  nothing = Array.new(7, " ")
  skeleton = ["(#{eyes[e]}#{nose[n]}#{eyes[e]})", "​ _|_ ​", "/[|]\\", "​  | ​ ​", "​ / \\ ​"]
  pumpkin = ["     ", "​  ,  ", "(#{eyes[e]}#{nose[n]}#{eyes[e]})"]
  fbat = ["​     ​", "​ ^\"^ ​"]
  rbat = ["​ ​ () ", "​ ​ ´` "]
  spider = ["​  |  ​", "​ .|. ​", "​ :\": ​"]
  spider.unshift("  |  ​") unless b == 1
  a = "     "
  bot = [nothing, skeleton, pumpkin]
  top = [nothing, fbat, rbat, spider]

  # if bottom and upper are empty
  if b < 1 && u < 1
    @output.push(nothing)
  # if bottom is empty
  elsif b < 1
    u < 2 ? (s = 3) : (s = 5)
    s.times {top[u].push(a)}
    @output.push(top[u])
  # if upper is empty
  elsif u < 1
    # put in white space before the decorations
    b == 1 ? (s = 2) : (s = 5)
    s.times {bot[b].unshift(a)}
    @output.push(bot[b])
  # if there's an upper decoration
  elsif u > 0
    # put in the top deco
    2.times {top[u].push(a)} if u < 3 && b > 1
    @output.push(top[u] + bot[b])
  end
  # Input the empty column
  @output.push(nothing)
end

# Transpose the array of arrays so that
# instead of outputting each line of a single each decoration
# what's output is each line of each decoration.
# Example:
# [[1, 2, 3, 4, 5], [1, 2, 3, 4, 5], [1, 2, 3, 4, 5], [1, 2, 3, 4, 5], [1, 2, 3, 4, 5]]
# [[1, 1, 1, 1, 1], [2, 2, 2, 2, 2], [3, 3, 3, 3, 3], [4, 4, 4, 4, 4], [5, 5, 5, 5, 5]]
@output.transpose.each do |data|
   data.each do |data1|
     print data1
   end
   print "\n"
end

The following:

ruby deco_g.rb 0000 0001 0002 0003 1110 1111 1112 1113 2220 2221 2222 2223 3310 3312 3321 3323

Outputs this:

          ()    |                 ()   .|.                ()    |           ()          |
   ^"^    ´`    |          ^"^    ´`   :":         ^"^    ´`    |           ´`   ^"^    |
               .|.  (¯w¯) (¯w¯) (¯w¯) (¯w¯)                    .|.  (^_^) (^_^)        .|.
               :":   _|_   _|_   _|_   _|_                     :":   _|_   _|_         :":
                    /[|]\ /[|]\ /[|]\ /[|]\                         /[|]\ /[|]\
                      |     |     |     |     ,     ,     ,     ,     |     |     ,     ,
                     / \   / \   / \   / \  (-o-) (-o-) (-o-) (-o-)  / \   / \  (^_^) (^_^)