That is exactly what you would need to do. 10.1.1 is an EXTREMELY OLD version of Indy. The current version is 10.6.2.
Be sure to read the install instructions first.
Yes, you need those DLLs no matter what. But you would still need an up-to-date Indy to take advantage of those updated DLLs and configure them properly.
It is very common for apps to use their own copies of OpenSSL DLLs, to avoid versioning conflicts, as the OpenSSL API tends to change from one major version to another.
It should not, since that folder should not be on the system search path, but even if it were, the DLLs should normally be looked for in the app's folder first. But, Indy does have an IdOpenSSLSetLibPath() function in the IdSSLOpenSSLHeaders unit if you need to specify exactly which folder Indy looks in for the DLLs.
The revision notes at the top of each Indy .pas file are EXTREMELY OLD, so just ignore them. They are a remnant from when Indy used TeamCoherence for its version control many years ago, before switching to SVN and now GitHub (neither of which store commit details directly in source files themselves).
Then you have an EXTREMELY OLD version of Indy installed and need to upgrade.
Not without upgrading, no.
See my comment above.