Overheard and understood

The other day, I was eavesdropping and I heard strange scraps of a one-sided conversation. Although I didn't get much out of it at first, I was able eventually to identify the speaker by his initials.

Well, if you're talking about breaking an old record, then yes, I take that very personally... Just get he and I together and you'll get all the aid you need... If you just give me a... well, I'll be very hard to get over, I'll tell you that much... Yes, if you give me the key and don't care about why, then you'll have your precious seaweed... Why are you referring to me with an archaic form of "you"? Is it because you want to hear me cry like a wounded dog? ... Can I start something at the theater? No, you've got me all backwards... Is my middle initial "I"? Buddy, I've had enough of your mouth.

The speaker's initials are:

LP - 'an old record'. The remaining parts of the puzzle rely on interpreting the phrases as describing combinations of 'LP' and other letters...

Just get he and I together and you'll get all the aid you need...

HE + LP = HELP ('aid')

If you just give me a... well, I'll be very hard to get over, I'll tell you that much...

A + LP = ALP (a mountain - 'very hard to get over')

Yes, if you give me the key and don't care about why, then you'll have your precious seaweed...

KEY - Y ('don't care about why') + LP = KELP ('seaweed')

Why are you referring to me with an archaic form of "you"? Is it because you want to hear me cry like a wounded dog? ...

YE + LP = YELP ('cry like a wounded dog')

Can I start something at the theater? No, you've got me all backwards...

'Something at the theater' is a PLAY - LP does not start this unless the letters are reversed!

Is my middle initial "I"? Buddy, I've had enough of your mouth.

LP with I in the middle = LIP (part of the mouth!)