I have a similar but simpler setup. The crucial difference in my setup is that instead of using full blown LaTeX, I use TeXMe -- https://github.com/susam/texme

I have a similar but simpler setup. The crucial difference in my setup is that instead of using full blown LaTeX, I use TeXMe -- https://github.com/susam/texme https://github.com/susam/texme -- which supports Markdown and LaTeX. So I write plain text files with Markdown + LaTeX, slap a single line of TeXMe JavaScript either at the top or bottom, and open the file with browser to see the rendered math. Like the OP I use Vim too with some customization with :ino and :ab. Nothing beats the editing productivity and convenience of Vim!