4. If the protocol you found for transforming lactobacillus is complicated, then it is undoubtedly because simpler protocols don't work.

Certainly, and that's why I haven't wasted my time trying a simpler heat shock protocol. The sonication work I've been doing is totally experimental, as I've found papers on sonication of yeast and papers on sonication of Gram-negative bacteria but nothing on sonication of Gram-positive bacteria. I'd think that if it were known not to work, someone would have said so already.

Regardless, electroporation of lactic acid bacteria is far simpler than heat shock, and it's what I'll be doing when I have the equipment.