On PC, tested Housemeld turning instants manifested into enchantments. Expected result: Housemeld does 3 things in order: exiles creature, converts the card to an enchantment (including reminder text that it removes other types), then places it on the battlefield. An instant flipped on the battlefield as a manifested card can't return to the battlefield because it's an instant, however Housemeld specifically removes the instant type and makes it an enchantment before attempting to return it, so it should be able to return.
Actual result: card was exiled but stayed in exile. Also, name was made purple to indicate a type change but the type itself was not changed. No actual perpetual change was noted on the card other than the purple name.

(also tested exiling a land and an artifact, both of which interacted correctly, returning to the battlefield, again leading me to believe this didn't because it's trying to put an instant on the battlefield despite the wording on Housemeld indicating removing that type and changing it to an enchantment first)

edit: conversely, if this is how you want it to function, you'd need to change the wording, placing the "becomes an enchantment" part after being returned to the battlefield.