I'd suggest giving it a try first. Rather than worrying about httpd.conf access, you can just use inbuilt tools to do that..
If your host has cPanel, you can host a Drupal multisite without manual edits to httpd.conf file.
Just make use of Parked Domain thin in cPanel correctly. All you need to do is, pointing extra domains to the main domain.
This is an article I authored a long time ago, for Domain Access module docs but I think it was updated several times to include cPanel and Direct-Admin specific instructions. It's not very limited to Domain Access. Just follow the same instructions.
In brief, if you "park" a domain, that's similar to aliasing. You can point any domain to the main domain that you purchased your account for. But you will not be able to point to an
addon domain which is a limitation for shared hosting accounts.
Also, as you have shell access, you can symlink.
I don't want to mention any commercial names. But if you really need to know a shared host that allow this type of multisites, that host's name mention an animal name.