1. The most likely reason for BitLocker settings being unavailable from a company account vs a local account on the same laptop is probably that your company domain has group policy settings enabled on domain members that disallow changing BitLocker settings from domain accounts.

2. If the problem lies in Group Policy then the only way to do so would be to contact your company and let them know that you'd like that setting to be visible and have them change group policy settings to do so.

3. Yes, your data is still being encrypted on the entire device, even when you're using your company account, because BitLocker is a system wide thing, so even if you encrypt with the local account, your company account still gets the benefits too.

Hopefully this is helpful