You want your shell stuff to work the same way even when you use a
different shell, or even a different box. Right?

If you use switchBashZsh you can attain at least most of what you
desire, perhaps even all. You can log out of Bash and log in with Zsh
(or vice versa) - and your aliases/exports/functions will continue to
work as before.

It gets better - if someday you need to use a different box with a
different OS, you can get your shell to work your 'normal' way in a
jiffy. Just save your $HOME/.shell directory on your primary box, and
paste it over your second box's $HOME/.shell (after running
switchBashZsh setup script on the second box). The second box need
not be the same operating system - switchBashZsh works across
FreeBSD / Linux / Cygwin.