I’m a bit confused, I believe the SNI issue was dealt with quite some time ago by making the default site on 35.185.201.91 to be the m1.escargot.log1p.xyz certificate/site. You can use MSN Messenger 7.5/escargot on XP just fine, as long as IE8 is installed (for TLS), TLS is on, SSL 2 is off and the root certs are updated, per your troubleshooting tool. And XP’s http.sys has no SNI support, regardless of IE version.
Then the next issue became the lack of a modern cipher suites that XP supports, the “best” being TLS_RSA_WITH_3DES_EDE_CBC_SHA, which wasn’t being supported by escargot/caddy at the time, but I believe valtron dealt with that, at least that’s when it started working for me and others on XP.
So I believe getting the TLS 1.0 support and the TLS_RSA_WITH_3DES_EDE_CBC_SHA cipher working on 9x would be the real issue methinks. Unless, I’ve missed something here.