Excellent thread open, asking good questions! Thanks.
First I think "GES" refers to "Grace Evangelical Society."
Here is a quote concerning their "gospel:"
No act of obedience, preceding or following faith in the Lord Jesus Christ, such as commitment to obey, sorrow for sin, turning from one’s sin, baptism or submission to the Lordship of Christ, may be added to, or considered part of, faith as a condition for receiving everlasting life (Rom 4:5; Gal 2:16; Titus 3:5). This saving transaction between God and the sinner is simply the giving and receiving of a free gift (Eph 2:8-9; John 4:10 ; Rev 22:17 ).
Thus they are advocates of "Easy Believism" and should be avoided.
I could not find the answer to your question concerning PSA.
The Greek words translated "propitiation" are 'hilasmos" (G2434) found in 1 John 2:2 and 4:10, which is a noun describing the means of appeasing God and turning aside His wrath. The other Greek word translated "propitiation" is "hilasterion" (G2435) is found in Romans 3:25 and Hebrews 9:5 (translated as mercy seat, the cover of the Ark of the Covenant). In this form the word points to the place where God's wrath is turned aside, thus Christ is the means of reconciliation or more directly salvation.
Related Greek words are "hileos" found in Matthew 16:22 and Hebrews 8:12, which is an adjective describing God being merciful, and "hilaskomai" (G2433) found in Luke 18:13 and Hebrews 2:17, which is a verb describing God action of being merciful by turning aside His wrath due to the sins of the people.
In summary the idea is that Christ provides the means of salvation, and those God places within Christ spiritually enter His propitiatory shelter, thus turning aside His wrath and being mercifully forgiven. He is the means of Salvation, but to obtain the benefit of His sacrifice, God must credit your faith as righteousness and place you individually within Christ.
I can't really tell if you're agreeing or disagreeing with GES. You seem to think that James 2 somehow expands Romans 4.
Oh and thank you for saying excellent thread and stuff.
Sorry, I was seriously asking questions, but now I am pretty certain on the issue, although I am open to reproof if adequately supported by scripture.