Same `:browser` target. There might be multiple builds if you prefer to have a separate script for each page, but then I'd also suggest looking into module splitting so you don't have to ship compiled libraries, including CLJS itself, with every page.
Regarding REPL - there's no need to run any REPL at all. I almost never use CLJS REPLs and almost always use a CLJ REPL, and shadow-cljs stays as a completely separate process that I just launch manually via its CLI.
If by "refresh or reload everything" you mean reloading the whole page as opposed to the built-in CLJS hot code reload - I think so, yes. Shadow-cljs has build hooks, you can reload the page via CLJS code in the `:after-load` hook.