Anniversary Blonde

Edison is a really weak caster, easy to assign to the fires. I do like nursery rhyme, though if you have another decent AoE caster might be fine.

Atalante's np makes a heap of stars, but I don't remember anything else particularly special about her, so as long as you have another AoE archer, I guess it's okay.

Emiya assassin has awesome animations, but I haven't played him enough to know how he compares. I think Beowolf is only meh for a zerker.

Really all comes down to one question: would you prefer to have the mystic code or those servants?

I really would not trade five SRs for that Mystic Code (If they are repeated servants it is ok). Anniversary blonde is pretty good, but you can live without it. I do not use Anniversary Blonde as much as I use Chaldea combat uniform or Mage's association uniform.

Anniversary Blonde gives only 1 turn of crit buster and a not very reliable guts. It is a good MC, but nothing spectacular.

I'd burn Beowulf, he spooked me so many times he's like Fionn to me. I don't know if he's good or not but there's many ST berserkers better than him.

Try not to burn np1 servants for rare prisms if you can. Even if you don't like them you never know when there might be some niche use for them, or an event where they have a special bonus. That said, in your list Edison is a good bet along with either Nursery Rhyme or Atalante. Emiya and Beowulf are pretty good.

I'd only burn Edison, Beowulf and Emiya assassin (Emiya only if you already have Shiki NP5). Atalante is a good semi support Quick and Nursery is a good caster crit art. Just wait till random Fionn or Stheno appears.

Consider your servant utility and gameplay quality before burn them, Atalante is a good Quick semi supp ( Quick supp is rare ).

Nursery Rhyme/Alice in Wonderland is an Art Crit NP spammer Caster ( her only rival is Caster Sheba ). If you know how good Art Crit team is, you don't want to burn her.

Don't burn Emiya assassin if you use Buster Crit team, he is a good Crit star maker + he has a targetable Taunt skill which is rare and at least he can save your hitter from random Crit or boss NP. He's a valuable servant you know !

For me, Beowulf and Edison is decent but if you have a better Zerker like Hercules or Caster like Casgil,Helena and maxed Hans you'll rarely use the 2 of them. You can burn them.

Also train yourself by using plugsuit, for Example a Jalter/Raikou/Gilgamesh/Rama/your Buster Crit DPS + Caesar + Merlin + Mozart can make sure you'll have a Guaranteed 100 % Crit !
Caesar has atk up + NP dmg up + Crit dmg Up + Crit star gen.
Merlin has atk up + Buster Up + Crit dmg Up + Crit star gen.
Mozart use 50 Crit star for guaranteed Crit plus a powerful Art card that can help Buster servants with not good NP gain.
Plug suit, Merlin second second skill, and Mozart second skill can at least help you survive enemies NP 3 times !

Buster Crit can use MC like default MC and Atlas, remember you're the Brain and servant is your weapon.
Control them !

Burning non-duplicate servants isn't worth getting RP imo
Even least useful ones are worth keeping just for their iterludes and drop bonuses in events

If i were you i'll save atalanta and emiya, atalanta become really good when we got skadi and emiya has targetable taunt