As the PPs said, as long as you know the person would like to attend MHP, then I think it would make a great present. Tickets won't go on sale until mid-year (assuming the timing remains the same in 2018), but you can give them a gift card with the funds (you'll have to estimate the amount - I'd take this year's price and add about 5% to 10% to be safe). There are a couple of cute Halloween Gift Cards available right now (
https://www.shopdisney.com/gift-cards/shop, click on "Halloween" on the right side menu to bring the Halloween choices to the top).
(The biggest draw back to the gift card is that it seems like there are some issues with using them online - sometimes, not always - so, if you're an AP holder, DVC or Disney Visa Card user, you might not want to put all of the funds on a gift card. I'd still consider getting the gift card - because it's cute - but only putting the minimum amount on it and then let them know you'll order the tickets for them when they go on sale.)