Saying 'conical fermenter' around him will get you a good lecture, and though my eyes tell me I'm making cleaner beer, he tells me I'm wrong and rants about how I'm ruining the beer by removing the trub for diacetyl rest. I see krausen and trub as something the yeast didn't want, so how is that going to make the beer any better?.
Who cares what fermenter you use? Only you should care. Use what you like. I've used glass carboys, plastic buckets, and Big Mouth Bubblers. My friends have used Fermonsters, Speidels, Stainless BrewBuckets, Spike Conicals, etc. There are pros and cons to all types.
Trub? My personal experience is it doesn't matter. The yeast either don't care, or they like it. My beer tastes the same with or without it in the fermenter. Avoiding it going from kettle to fermenter doesn't necessarily mean clearer packaged beer. (see Brulosophy) But do whatever you like. It is your beer.
The point of the Diacetyl rest is for the *yeast* to clean up after themselves. I will admit if you crash first, rack off of the yeast and then raise for the rest, you might inhibit that process a bit. (less yeast in suspension, and they have to wake up from cold sleep first) But if you don't have Diacetyl issues with your beer, then keep doing what you do.
Don't even THINK about saying 'cold-crashing' or "BIAB" to him.
Cold crashing is the easiest way to clarify a beer prior to packaging. It only takes time and the ability to get <32℉. (but stay above 28!)
He frowns at BIAB? Ha. Ignore him. If you want to use that method. Use it. BIAB brewers have more medals, gold or otherwise, than that guy, I can assure you. And if he's a judge, I'd bet him a keg of beer he's judged BIAB beers without knowing and given them excellent scores. I have a friend that uses a 3-vessel gas-fired Spike HERMS system with a basket, but still uses a bag for easy cleanup.
This shop guy sounds like a jerk. Buy what you want. Never accept what you don't. YOU make substitution decisions if he doesn't have or can't get what you want - not him.
So far, my take on having a mill is that a 2-roll mill is fine, though running the grist through twice may be required, according to some opinions. Knowing how they work, I can see a 3-roll mill being (some?) better than a 2-roll mill, but not enough to warrant the bigger investment. I'll take the difference and use it for an electric one (don't have to get the drill out). But I had to ask. Wider mills will process more grain, obviously, however, the rolls will also flex and affect the grist size / efficiency. I'm not in a hurry anyway, but I don't think I want to stand there hand-cranking 8 pounds of base malt through one of those things. Electric drive, it will be.
By all means, go with a motor if you can. I have a MM-2 Monster Mill and use a Dewalt ½-inch drive 8A drill. It takes a minute or so for 10#. I have a feeler gauge, and I crush once at 0.035˝ and a second pass at 0.030˝. (I do BIAB) My friends have an MM-1. Sometimes we stack them with 2 drills and double crush at different gaps in one pass. I guess a 3-roller, like their MM-3 would be the ticket here except most of those can't be adjusted on the 3rd roller. But it is little effort to do it yourself with one mill, a feeler gauge, and 2 buckets. You don't need long rollers for homebrew. That new Spike mill looks sweet by the way.