Can you use Danish Oil after using linseed oil?
Yes, by all means. You might want to test a spot (not for "will it work" - it will - but for any possible color issues.) 

As for what you have read, consider it an opinion, nothing more - if you like what you have, boiled linseed is just fine. Apart from some potential risk to tree nut allergy sufferers, walnut oil also works nicely and is a drying oil. Pretty much all the oils can be recoated and/or coated over one another with little issue if the previous coat is dry/cured.