I'm a minimalist. Here's my 2 cents.
Pedals - yep. You need 'em. Get the cheapest that you feel comfortable riding with unless you're someone who worries about efficiency vs effort and/or effort vs speed. For me, platforms with cages worked well with diamond frames though I eventually learned to use SPDs. Personally, I'll never spend over $30 on pedals again (go eBay!).

Helmet? Maybe... it's a divisive issue. Some people wouldn't ride without one on any ride... some believe it's a $$ waste. Only you can make that decision for yourself. Me? I wear one - sometimes, but usually only when required as part of RUSA or other events.

Cycling shoes? Um, not needed though they can be comfortable and "more efficient". If you're going to ride with platforms and cages, then they are less "necessary". What you do want, though, is a stiff lower/sole. Then again, thousands of people have ridden across country in 50s-70s era Converse Allstar style basketball sneakers. I wouldn't spend money on expensive shoes when starting out.

Lights? Are you going to ride at dusk/dawn or other periods of low light? If not, then this could definitely be more wasted money. Some claim they help you to be seen - unfortunately being seen doesn't preclude being hit despite having really bright lights all around. Then there are the issues batteries vs dynamo and cost/convenience vs reliability/effectiveness.

Cycling gloves? Got 'em, use them sometimes. Don't feel they are really needed. YMMV.

Pump - no need for 2. Get one that can be carried with you. This is the one area of accessories that I do recommend you don't cheap out on. I carry a mini-pump with a gauge that is small enough to fit in my jersey pocket if needed and yet can pump my tires to 110 psi. I spent about $55 on it a couple years ago.

Bike bag? Maybe. How far are you going to be riding? The farther away from your starting point, the more beneficial it might be. What do you really think you'll need to carry - emergency tools, spare tube or repair kit, what? Cell phone? Are you going to be in traditional cycling kit or casual clothes with multiple pockets? My last diamond frame bike had a rear rack and Arkel Tailrider bag stuffed to the gills... but I rarely needed much of what I carried (probably weighed 10-12 pounds loaded out - WAY TOO MUCH STUFF!!!!). Otoh, I routinely rode centuries with just a multitool, 2 water bottles mounted on my frame, and a spare tube in my back/jersey pocket. No cyclometer, no GPS, no cellphone, no extra food...
--Think about overkill vs emergencies/necessities and weight vs mass issues. Sometimes less IS more. Other times, that extra 2 pounds you lugged uphill for 80 miles makes the difference between finishing a ride and making the call of shame for a lift home.

Lastly, I ride recumbents now and, while the frame is different, the issues remain the same - overkill vs emergencies/necessities and weight vs mass.

Sorry if this seemed pedantic or condescending. It's not meant to be. You can overthink things - don't do that. Get ut and ride... let experience and/or people you meet up and ride with teach you what you need.