BT’s and gerim may struggle to pick up the “shprach” and mannerisms of the community.
My suggestion: have them read the dictionary of Yeshivish, Mendel Harduf’s dictionary, and Webster’s Hebrew-English dictionary. This will help with language.
The worst baalei tefillah I’ve ever observed in my entire life are the Yeshivish. When I was a kid, our Reform cantor knew nusach, including Lewandowski and Sulzer. Instead of the sublime sound of our traditional nusach, and stunning synagogue music written by Sulzer and Lewandowski, many of our minyanim employ Benny Friedman, Yaalili, and other popular tunes from the amud, r”l.
It’s sad to say this, but the cantorial arts have been far better preserved by the non-Orthodox.
In response to giyur, if a ger decides to renege on his commitments, he’s the one who will have to answer to God in the long run. Accepting the rewards and punishments associated with being obligated in the mitzvot is the definition of kabbalat ol ha mitzvot. A bet din can and should be sensible- i.e. don’t convert someone who lacks a kosher kitchen, or don’t convert someone who has a hard time getting off work early for shabbat and taking off for holidays, etc. Common-sense approaches are needed.