No magic item will have all the adjustments necessary done just by adding it to the inventory sheet. If any changes to "To Hit", damage, AC, strength, dexterity, constitution, intelligence, wisdom, charisma, saving throws, DC, etc. are needed, use the Start page and perhaps the Spellcasting page. All of that has to be done, manually, making the appropriate adjustments as needed.
There are no plans, now or in the foreseeable future, to implement non-official WOTC material in this tool (and none at all of any 3rd party materials, either). Unearthed Arcana (UA) material is not official material. Nothing released as UA material will be implemented in this tool. Not UA classes, not UA spells, not UA feats, not UA backgrounds, not UA magic items, not UA monsters, not UA pets, not UA anything-else-you-might-think-of. IF the UA material eventually gets released in a WOTC official form (hardcover book or PDF to support the adventurer's league) I am reasonably confident it will then be implemented, but not before.
Completely new class? Not supported. Want more than 3 classes? Not supported.
And the Start page will not be unlocked. The answer is no.
I am sorry if my comments seem a bit harsh, but we have a Community FAQ for a reason. Please, PLEASE read it before you ask questions that have been asked (and answered) many times before. And then re-think your question again before you decide to ask it anyways.
(Grumpy halfling wanders off, wondering what he'll have for his 3rd supper...)
