The Holy Numbers

Ruby, 109 105 95 82 bytes

->n,h{(?0..?9*99).select{|x|x.count('469')+2*x.count('80')>=h&&/[12357]/!~x}[n-1]}

This is the terrible "calculate from 0 to 99999999999..." approach that happens to be 13 bytes shorter than its lazy counterpart. However, this version is unlikely to finish before the heat death of the universe. Worth 13 bytes, anyway ¯\_(ツ)_/¯

You can test it for smaller values by changing ?9*99 to, say, '99999'.

Here's the old version (95 bytes, with lazy evaluation, which runs near-instantly rather than near-never):

->n,h{(?0..?9*99).lazy.select{|x|x.count('469')+2*x.count('80')>=h&&/[12357]/!~x}.first(n)[-1]}

->n,h{
(?0..?9*99)  # range '0' (string) to '9' repeated 99 times, way more than 2**64
.lazy        # make the range lazy, so we can call `select' on it
.select{|x|  # choose only elements such that...
 x.count('469')+2*x.count('80')  # naive holiness calculation
 >=h         # is at least h
 &&/[12357]/!~x                  # naive "is holy" calculation
}
.first(n)    # take the first n elements that satisfy the condition
[-1]         # choose the last one from this array
}

Pyth, 32 bytes

e.fg*g.{`46890J`Z++lJ/J`8/J`0QE0

Explanation

                                 - autoassign Q = eval(input())
 .f                           E0 -  first eval(input()) terms of func V starting Z=0

     g.{`46890J`Z                -    Are all the digits in Z in "46890"?
               `Z                -      str(Z)
              J                  -     autoassign J = ^
     g                           -    is_subset(V,^)
      .{`46890                   -     set("46890")

    *                            -   ^*V (Only return non-zero if only contains holy numbers)

                 ++lJ/J`8/J`0    -    Get the holiness of the number
                   lJ            -      len(J)
                  +              -     ^+V
                     /J`8        -      J.count("8") 
                 +               -    ^+V
                         /J`0    -     J.count("0")
   g                         Q   -  ^>=Q (Is the holiness great enough)
e                                - ^[-1]

Try it here

Takes input in the form h \n n

Python 3, 103

lambda n,h,l='4698080':[y for y in range(2**64-1)if(sum(l.count(x)-(x not in l)for x in str(y))>=h)][n]

Here's a solution that uses a more memory efficient approach, but otherwise uses the same algorithm if you want to test it.

l='4689080'
def f(n,h):
 c=i=0
 while i<n:
  if sum(l.count(x)-(x not in l)for x in str(c))>=h:u=c;i+=1
  c+=1
 return u

Test cases:

assert f(3, 1) == 6
assert f(4, 2) == 44