Yeast, hops, and character malts (in your case, the crystal and amber malts) drive the flavor more in that beer than the base malt will.
As a Brit, I couldn't disagree more. I grew up in northern England with bitters that
had little or
no speciality malts, you can still make great bitter without them as long as your base malt is characterful enough.
More importantly, bitter is all about the balance between malt, hops, yeast, water and carbonation, and it's really easy to screw up that balance by overdoing the speciality malts.
Also pilsner tends to thin out beers, a traditional English malt gives you more body which you need for this kind of beer.
Any suggestions on ppm of SO4?
Also what would be a hop schedule you would recommend and with which hops? I will have to get hops regardless.
I really only have those specialty malts in there to get some color per guidelines. It works out to 4 oz of each.
I’m also open to a different dry yeast option
That's the classic mistake foreigners make with British beers - never try to hit a colour target using "flavour" ingredients. British brewers always adjust the colour with brewer's caramel or a tiny amount of black malt, so adjusting with flavour ingredients will end up with something that tastes wrong. And as you can see from
pictures on Untappd, some of the greatest English bitters are really pretty pale.
USians tend to go too low on minerals, in general go for 2:1 sulphate:chloride and at least 200ppm sulphate for southern bitters, more than 250 for northern ones.
In British commercial brewing there's a lot of different hops get used and it's a great style for showing off different hops, so get too hung up on a particular variety. Saying that EKG is my favourite hop, and I would never argue against using it in bitter, it is the benchmark for the style. But the likes of Challenger and First Gold work well; whereas some people love Fuggles and others are not so keen - if this is your first bitter then I would probably avoid Fuggles to start with in case you're one of the people who don't like it, it's better in dark beers. But if you're on a budget and things like Savinjski Goldings or Willamette are cheaper than EKG, then it's OK to use them.
In general you need to start with the final ABV - the sweet spot is around 4.3% - and then work backwards. The attenuation on your yeast will tell you the OG you need to hit 4.3%, then use the BU:GU ratio to work out how much bittering you need. 31 IBU in 1.046 is a bit low, even for southern bitters which are typically around 0.75 BU:GU, and in the north you're looking at 0.8-0.9, so for my (northern) taste I'd be looking at more like 39 IBU in a 1.046 beer.
The bittering hops don't have to be British, you can use Magnum or something if that's convenient, on the other hand if (like here) your hops come in 100g packs then it can be convenient to use the whole pack in one brew, for bittering and late additions. Add the bittering at 60 min, some at 10 min, then I generally put a bit in the whirlpool and a generous amount as dry hops.
If you're restricted to dry yeasts (as opposed to eg harvesting yeast from a bottle of Fuller's 1845 or Lancer/IPA) then S-04 is OK, Windsor followed by Nottingham/Munton Gold at high krausen is traditionally about the best option but I'm hearing lots of good things about the new Lallemand Verdant for English styles so you could try that if you can find it. Even the Lallemand Voss fermented not too warm could be an option.
Even if proper English malts don't fit the budget, I would try to find at least a local pale malt rather than pilsner.