That's a good idea!
I think that LWP::UserAgent will only load the SSL libraries once it encounters an https URL. To be really sure, you can try to load LWP::UserAgent only from within each thread. This has other drawbacks, but at least for diagnosis, maybe it helps:
#use LWP::UserAgent; # don't load this in the outside program
my $a = threads->create(sub () {
require LWP::UserAgent;
my $ua = LWP::UserAgent->new;
$ua->ssl_opts(verify_hostname => 0, SSL_verify_mode => 0x00);
};
Thinking more about this, I'm less confident that this approach changes much, at least if the C part of the ssl library still only gets initialized once, but as it's a small change, I think it's worth a try.