I intentionally kept it very simple to let it stay as original to its true harmony as possible, adding only a few other lines (a third violin playing a bit higher than the first violins playing the melody).
Can I ask what the intention was to mock it up? I know you say you wanted to keep it simple, but I tend to think you could do a lot more with it. It seems unfinished.
Also, just a note on speed. People have a tendency to play hymns too fast, and I think that's the case here. It's often sung slower than this as a congregational hymn, and as a string piece I'd say it would work better slower also.
Have you looked at other alternative piano transcriptions for this to use as a base? IMO, there are better arranged versions out there that manage the pedal notes better.