Consistency Within vs. Across Devices

I have a question geared more towards UI/UX Consistency rather than Branding Consistency.

We have an ability to "Save to Lists" on our website. On our desktop site, it is a dropdown. On our mobile site, it's a button that opens a modal (our company loves modals...).

We're looking to add this functionality to additional pages on the site. In this instance, there are three options:

1) Have a link on both sites that says "Save items to list". On mobile it would open a modal (consistent with other mobile page) but on desktop it would either open some type of flyout or a modal (inconsistent with other desktop page).

2) Have a dropdown on desktop (would act consistent with other desktop page) but on mobile the dropdown would be an entirely new treatment (dropdown, but pop modal only for a new list).

3) Use a dropdown on desktop (consistent with other desktop page) but a link on mobile (would be similar to other mobile page in interaction).

I hope this makes sense- tried to give a clear picture without giving an overbearing amount of information. Just trying to figure out the right path with stuff like this. Thank you!