word - Like totally amazing interchangeable sister outfit accessory swapping or whatever

OMG, me and my sister are like total BFFs and we share clothes like all the time! We soooo have the same sense of style and we borrow stuff from each other like every single second!

We don't even care, like, who was the last to borrow what from who or whatever. We can work anything into our outfits no matter what and make like a totally new outfit every time! And we always look so cute!

Seriously, the one thing is, we like never ever ever wear the same outfit twice. That would be so embarrassing you could just die! You know what I mean?

Anyway, check it out:

Take sisters CASTLE & OATHS through 6 more outfits
by lending/borrowing one "accessory" (letter) at a time


------------------------------------


Solution:


CASTLE          OATHS
  |           .   |
  |         .     |
  |        S      |
  |      .        |
  v    .          v

CASTLES         OATH
  |    .          |
  |      .        |
  |        L      |
  |          .    |
  v            .  v
CASTES          LOATH
  |    .          |
  |      .        |
  |        E      |

  |          .    |
  v            .  v
CASTS           LOATHE
  |           .   |
  |         .     |
  |        O      |
  |      .        |
  v    .          v
COASTS          LATHE
  |    .          |

  |      .        |
  |        S      |
  |          .    |
  v            .  v
COATS           LATHES
  |    .          |
  |      .        |
  |        O      |
  |          .    |
  v            .  v

CATS            LOATHES

(At this point, I typically remind solvers that my puzzles only use well-known words, but these tandem chains are difficult to construct without a few near-slang words. So be prepared for an occasional ding, ting, zing, bling, cred, or dang.)

See if you can help these 5 sister pairs change their outfits:

1.  Take sisters SAND & PILE through 7 more outfits by lending/borrowing one "accessory" (letter) at a time


2.  Take sisters TRIED & GINS through 7 more outfits by lending/borrowing one "accessory" (letter) at a time



3.  Take sisters BEERS & TAPS through 7 more outfits by lending/borrowing one "accessory" (letter) at a time


4.  Take sisters SCORED & CUP through 8 more outfits by lending/borrowing one "accessory" (letter) at a time


5.  Take sisters COOTS & BATS through 8 more outfits by lending/borrowing one "accessory" (letter) at a time

---

Epilogue:

Extra super double credit to @osdavison @Brandon_J and @Dolgubon for coming up with longer chains than I had prescribed!

See the sequel here

Answer

Completed answer:

SAND & PILE (I can get 8, one more than expected)

AND & PILES --> LAND & PIES --> LANDS & PIE --> LADS & PINE --> LEADS & PIN --> LEAD & PINS --> LED & PAINS --> SLED & PAIN

TRIED & GINS (7, as expected) - partial credit to OmegaKrypton - please go upvote his answer!

TIED & GRINS --> TIE & GRINDS --> TIES & GRIND --> TIDES & GRIN --> IDES & GRINT --> IDE & GRINTS --> NIDE & GRITS --> NIDES & GRIT

BEERS & TAPS (7) - osdavison has an independent solution with 11 words; please go upvote it.

BEES & TRAPS --> BEETS & RAPS --> BESETS & RAP --> BESTS & REAP --> BEASTS & REP --> BEATS & REPS --> BETS & REAPS

SCORED & CUP (8, as expected) - credit to Gareth McCaughan - please go upvote his answer!

CORED & CUPS --> CRED & COUPS --> CURED & COPS --> CURD & COPSE --> CURDS & COPE --> CUDS & COPER --> CUD & COPERS --> CRUD & COPES

COOTS & BATS (8, as expected) - PartyHatPanda has an independent solution - go upvote it!

COTS & BOATS --> COSTS & BOAT --> COASTS & BOT --> COAST & BOTS --> CAST & BOOTS --> CASTS AND BOOT --> CATS & BOOST --> CAT & BOOSTS