Hey Peachlander,
Well "must haves" are a very personal choice for everyone ...but since you asked...

1. A
good DI unit that is 1. tonally transparent (when set flat, of course), 2. 100% dead silent 3. has a good-sounding tone stack. To me, these three points are a must, and a good DI will make any decent pickup system sound better in the house, and a good system sound stellar! Not to mention a "must" if you ever plug in different acoustics. Personally, I like the Baggs Venue and anything Radial for this task.
2. A good delay. I prefer delay over reverb. I like verb, but most PAs and/or house setups will already have reverb on board. This, and reverb can muddy-up your live house tone in
very quick order, so little (to none) is my preference when live. Short delay (slapback), OTOH is reallllly good for thickening and "enlivening" your acoustic tone. Used judiciously, it's almost "unnoticible" in the house unless you turn it
off, then suddenly your guitar sounds thin and naked. I've personally found short delay is my always-on pedal as it "livens up" the overall tone without really sounding like "an effect," per se. And for "real" delay effect, use another pedal or another preset. You can't go wrong with strymon, yikes that stuff is good! But it's on the steep side for me, but even more it offers me far more applications than I need. Thus on my acoustic board it's simply a CarbonCopy for slapback and Flashback for tap-tempo or "real" delay duty. But on my electric board, I have TC's Nova Delay: outstanding! Offers 9 presets (of which I use only 5), very flexible in its tones and types, and user friendly (quick on the fly). I highly recommend the Nova Delay (or the Flashback 4x, too) if you want a more feature-laden delay without paying for a Stry Timeline (but again, Strymon's seemingly infinite number of algorithms really are tasty ...just sayin).
3. Yeah, reverb

But as per my point #2, I leave the "ambient" reverb up to the FOH guy. My reverb pedal is truly purposed as an effect, so it's typically set heavy, and stomped in for this or that passage, intro, or whatever, then stomped out. I like TC's HOF reverb for heavy washes, but frankly there are lots out there that are just flat-out good (e.g. the Digitech Hardwire is likewise killer, if not a bit large in size). And IMHO you must check out the latest Boss iteration(RV6, IIRC) as it's washes are deep and lush! But for a mini pedal(s), the HOF and Flashback minis are awesome in their tone, sacrificing only a few features to achieve a very small footprint. And of course, the Blue Sky, and certainly Big Sky, are superb-sounding units that offer everything I could ever see needing in a reverb-as-effect unit. Were my needs more demanding (or were I a better player), I'd consider one.
4. OD if you're nutty like that. See my previous thoughts

That's it for me on the "must have" pedals. Probably ditching the chorus as I rarely use it. Hope that gives you a few things to think on

Edward