In my opinion, a company name with a & is a trouble for domain names.
As you said, you need to find alternatives because you can't register a domain name with a & in the URL.
The main disadvantage I see is you need to register many domain names to cover all alternatives of the & in relation to the language of the users. And in your case, you can hope all these domain names are available.
You most probably know the C&A company. If you analyze their domain names, you can see they have many domains names to cover alternatives for each language. Example:
- for English users:
www.c-and-a.com
- for French users:
www.c-et-a.fr
- for Spanish users:
www.c-y-a.es
- ...
Moreover, C&A needs to protect domain names they own. That's why, they most probably also registered all TLDs of c-and-a, c-et-a, c-y-a, etc. Compared to a single domain name with each language on a subdomain, it costs much money to register a domain name per language.
However, it's not impossible, you can copy the C&A system. For branding, they always use the term C&A. For SEO and Google, there is no impact because Google bots will analyze your domain without a &.
For Google users, this is not a problem because Google knows that & is a synonym of and. So, they can type one or the other, Google will show up your site in the SERPs (this is the case for C&A). If it's the case yet, you can work on branding on the Internet and Google will understand that this is the same company.
