Okay so for the twins i would've recommended queen flying slime mount. Try it and believe me. (Never play expert or master but beated like this the twins)
Though summoner may be not as bad as i thought, I still only use melee because it does the most damage and defense and I just do best with it, and besides, you can still use summoning items just if you find them, it doesn't downgrade your class, so I typically go with best melee armor, best sword I can get my hands on, and if it's cheap and decent or if I find it I get a summoning weapon just so it can do more damage
Supposedly it's not impossible to get the hellwing bow before fighting bosses it just takes some insanely improbable world gen. Haven't confirmed but that's what I'd heard. Something along the lines of dungeon gold chests spawning within reach of the above ground dungeon and looting gold keys from pots.
ok this is cool. now do it in infernum hardcore on the zenith seed with 1 hp and no armor or accessories in space with your pc unplugged hanging upside down with no hands blindfolded backwards in less than one hour.
you had to grow wheat to complete the community center bundles, unless you found 10 wheat in total at the traveling cart throughout the run. if you touched that wheat at any point, you touched grass.
you may or may not know this already, but a featherfall potion does the same thing as the umbrella also, you can hold down to fall faster when you are using the umbrella (or hold attack which will let you pulse the falling)