I’m helping a friend recover Bitcoin from an old wallet dating back to 2010. The laptop is long gone, but luckily there’s a printed sheet with the following details:

1 Bitcoin address (confirmed to hold BTC)
1 public key (same in all entries)
3 different private key-looking strings
One is 32 characters, starts with HDr…
Two are 64 characters, start with oUC… and MHC…
3 different rmd160 hashes (possibly compressed vs uncompressed?)

All the public key and address fields are identical across the entries, which suggests these private keys might be different encodings or formats of the same key,  maybe raw hex, WIF, or Base58. This was common in early wallets or custom scripts that didn’t follow today’s standards.

Questions:
   1. Could these be the same private key in different formats (e.g., hex, WIF, Base58)?
   2. What’s the best way to decode and test which key is valid for the address?
   3. Can Electrum or another tool help me test them safely offline?

Any guidance or recommended tools would be hugely appreciate.  I’m happy to share more details privately if needed.

Thanks in advance!