Long story short: I follow Yekkish minhag all around (a DNA test showed I am actually Sephardic, but this is not an issue according to a leading Posek who told me not tochange my minhag). I do not do Mayim Achronim as Yekkes do not have the custom. I know the SA and MB regarding Mayim Acronim as well as the Tosfos. My question is this: Should I have Mayim Achronim available for my guests that have the minhag (or follow the halacha if you wish to say)? I wash before Kiddush, whould my guests wash after kiddush?
99 percent of my guests say “We’ll follow what you do.” Is this correct? One single guy who eats by us was told by his Rav to go to the sink and wash Mayim Achronim before bentching. Should I invest in a Mayim Achronim cup for my guests and just not do it? Start doing it?
You certainly don’t have to deviate from your customs, and it is fine for guests to follow your customs when they dine at your home.
This is certainly true for the order of kiddush and washing, though you can of course tell your guests in advance that they should feel comfortable to wash in between if they wish to do so.
For mayim acharonim, those guests who are particular to wash mayim acharonim should do so even in your home, but this does not mean you have to invest in a special mayim acharonim cup: It is fine to allow the guests to go to the kitchen (many do so anyway), or to use a regular cup for purposes of mayim acharonim.