Is there any spells, features or feats that allow a PC to temporarily use another creature's features without Shapeshifting, Polymorphing,Wild Shaping, E.t.c?

It's for a Kirby build if your wondering.

The only way I know of would be a lv17 Arcane Trickster Rogue which can steal a spell to use as their own but that isnt an option for me due to my character being lv6 and having no Rogue in it whatsoever. Thx for the help in advance. 

Nope.

The nearest Incan think of the Bard's Magical Secrets, but at this point, it's not going to be available much sooner than Spell Thief and brings its own problems due to MCing. It's also not as flexible as Spell Thief, wjic is a problem given your trying to mimic Kirby.

I'd also consider why Spell Thief is a L17 ability. Granted, there is significantly more power behind than Kirby's (effectively counterspells at the same, blocks enemies from using that same spell again), but when you consider Magical Secrets, a much less powerful way of getting spells (ok, it lasts longer, but you can only do it twice at each opportunity versus any time someone casts a spell you), is granted at L10, then your Kirby attack must be valued at being worth above L10. Is that something you feel you'd want/be able to invest in?

Quote from Linklite >>

The nearest Incan think of the Bard's Magical Secrets, but at this point, it's not going to be available much sooner than Spell Thief and brings its own problems due to MCing. It's also not as flexible as Spell Thief, wjic is a problem given your trying to mimic Kirby.

I'd also consider why Spell Thief is a L17 ability. Granted, there is significantly more power behind than Kirby's (effectively counterspells at the same, blocks enemies from using that same spell again), but when you consider Magical Secrets, a much less powerful way of getting spells (ok, it lasts longer, but you can only do it twice at each opportunity versus any time someone casts a spell you), is granted at L10, then your Kirby attack must be valued at being worth above L10. Is that something you feel you'd want/be able to invest in?

Be able to yes, want no because I don't think Bard would suit Kirby for this specific Kirby build because I am basing him off of the Super Smash Bros Ultimate version, right now he is just a Fairy for race, Blood Hunter lv2 (For the flaming hammer),with Fighter lv1 (For the Fighting Style and the Action Surge at lv 2), and Sorcerer lv3 for Green Flame Blade (for the sword) , Feather Fall and Disguise Self for copied appearances.

At this point I may make a HB copy spell and hopefully get my DM to approve it.

Isn't the MCDM psion class going to revolve around on learning monster abilities? It's a third party product and won't be compatible with dnd beyond, but it sounds like that you're talking about. The class is going to be called The Talent I think. 

You could go for a Druid and flavour your wildshapes as learning certain abilities (for instance rather than using wild shape to turn itno a wolf you just learn its abilities to move and sense things and grow claws), although these would be limited to beasts unless you go for Circle of the Moon to get Elemental shapes. An accomadting DM might be able to homebrew it a bit more to give you a bit more range but it would really depend on what abilities you are looking for.

Quote from Rob76 >>

You could go for a Druid and flavour your wildshapes as learning certain abilities (for instance rather than using wild shape to turn itno a wolf you just learn its abilities to move and sense things and grow claws), although these would be limited to beasts unless you go for Circle of the Moon to get Elemental shapes. An accomadting DM might be able to homebrew it a bit more to give you a bit more range but it would really depend on what abilities you are looking for.

 I am mainly looking for copying weapon attacks and spells. Im sure I can work out something with my DM since he's pretty accomadating to HB.