Did she explain why to use the stretch needles? That puzzles me too. A stretch needle has more of a ball point, which I would think would make it harder to sew batiks, which are more tightly woven in the first place. Ka-punk, ka-punk, ka-punk..... I'd look for a topstitch needle.
About the silicone spray.... I'm not saying you HAVE to use it. I'm saying test the quilting out first, using the same fabrics and same batting. If you have tension issues that you can't resolve, THEN try the silicone spray. If your friend is nervous about using it, have her bring some scraps from her quilt and test the spray on them.