Welcome. You have set yourself some impressive tasks (disclaimer: none of which I've done). Fortunately, it's a fairly well trodden path and using google to search this site reveals many threads:
https://www.google.com/search?client...ked+conversion
Plug and play gauge might be harder to resolve. Koso are another manufacturer of (expensive) aftermarket gauges but their plug/play SV adaptor is only for fuel injected models.
https://kosoeurope.com/en
If you are soldering averse there are OEM style plugs/sockets available which use crimped connections. Soldering is a good, basic skill to learn though (desoldering from a printed circuit board is harder - for me at least)
Weatherpack make good waterproof connectors too
https://tinyurl.com/y5h4322k
(had to shorten the url)