Trouble getting multi domain certificate installed at Bluehost

I own several domain names and obtained a multi domain certificate from LE which is installed at Bluehost, my ISP. My primary domain is https://propertylinemaps.com and it works fine although I need to fix the mixed content and tweak my .htaccess file.

My other domains are “add on” domains. All my domains are under one “business pro” account on the Bluehost cloud.

Alas, my addon domains do not point to my certificate. Instead they point to a wildcard certificate issued to Bluehost itself (*.bluehost.com). See for example https://usnggrid.com

I have made several calls to tech support. One thing I learned is that for a multi domain certificate they have to do a manual install.

My account is being serviced by the following versions:
CentOS Linux redhat 4.4.7-16
Apache 2.2.31
cPanel 11.52.5

Question: Can anyone point me to info that I can pass on to Bluehost that might show them how to install my multi domain certificate so that my addon domains correctly point to my certificate instead of pointing to a wildcard certificate for Bluehost itself?

BTW, I asked if they support “Server Name Indication” for the type of account I have and the answer is “no”. If the answer had been ‘yes’ then I simply would have got one LE certificate for each domain and been rolling.

OK, I talked to another Bluehost tech and he indicated that to get my multi domain certificate working for my ‘add on’ domains that I needed to edit .htaccess.

Yes, I know about editing .htaccess to redirect http to https, etc.

But he pointed me to this article with info about wildcard SSL and said I would need to do something like this for each of my ‘add on’ domains.
https://my.bluehost.com/cgi/help/766

Does that sound like good advice?
Is there any related documentation here at LE that I missed?