Calculated Multiple Lookup Values

HELP!  I've taken a new position that utilizes Power Bi heavily and I'm trying to run a new column (A that takes my 'Accessorials' column and references two other tables in order to populate all possible results.  This is coming from a SQL Stored Procedure, which when ran manually, referenced an XML hierarchy file.

Accesorial.Text = LOOKUPVALUE(AccessorialModeLTL[Attribute.Text], AccessorialModeLTL[Attribute.Value], '4-1 StoredProcedure Query'[Accessorials])

When I run this basic lookup formula, I only get accessorials if they only had one listed attribute (many rows have this field null as they have no accessorials)-- Any row that has more than one accessorial doesn't return anything.  I need a list of all accesorials  delimited by commas, so that we can evaluate the prices based on which "add-ons" were included in this price

Lookup Table (heiarchy) #1:

Lookup Table (heiarchy) #2:

I have attached both of the lookup tables in .xlsx format for a more detailed scope of the data and lookup options.  So, I kind of have two questions:

1) What formula can I use so that all lookup values from my two tables are included in the output column?-- Keep in mind I have two lookups  (the first lookup gives a 1 for true and 0 for false, the second lookup actually references varchar lookup values)

2) Is there a better (beginner) way to model & reference this hierarchy so that the end user can only see the ouputted accesorials instead of the [pu_lifgate:1], [trailerfeet:9], [trailerfeet:11], etc. format?

Flattened Accessorial Table #1 (True/False)

Flattened Accessorial Table #2 (Varchar)

Original XML Hierarchy File 

Any help is greatly appreciated, as I may be in a bit out of my league here.