While I will agree (with the later addition of Stacy you made) that these are very popular, also for me, of course you can have a whole playthrough without Daisy and either Lyssa or Min getting close to you. After knowing the choices I will have them but a first time player may not, so I don't know whether I would call them "main" LIs. The girls "always around" are Lydia (Ms McGuffin and a plot device but we don't know whether the devs intended to make us care), Stacy (who we can keep as an innocent sister if we so desire) and AmRose.
Then again you are correct that the characters you chose have way more fleshed out emotional relationships with Mike than the others. So maybe, despite them being optional, they are intended to be the "canon" path?