Hey Beth,
It looks like you did a great job transposing.
The only change you may need to make is the A should be transposed to an F#, not F#m. If it was Am, then you would transpose to F#m. A major is not that common in the G chord family, although it does happen in some cases, like here. You may be able to get away with F#m, but if it doesn’t sound right, you’ll probably need F#, which you’ll have to play a barre chord for, unfortunately.
Without playing the song, I can’t tell for sure if B7 would work. But my guess is that it would not in this case. This is an old hymn, and there are no other 7th chords present, and there are a lot of other chords being played. All of this makes me feel as though the B7 wouldn’t work very well. However, it’s always worth a try. See how it feels when you play it in the progression.
You never fail until you quit!