See Choranda, Fungal Priestess.

It does look very weird to have a planeswalker with a ability. I can see why you did it in this case, but I do prefer Choranda's way of doing a land planeswalker, using a loyalty ability to generate mana.

It does look rather off, doesn't it?

I also wonder if the loyalties on these are much too low. I mean, you could kill a land with a Lightning Strike the round it enters the battlefield. That's rather disheartening.

I know that's supposed to be part of the drawback. But Choronda also has the drawback of the mana only coming at Sorcery speed. That should be enough of a restriction to allow you to bump the starting loyalty to something like four or five. If a person knocked my Planeswalker/Land off the battlefield with a Lava Axe, I'd probably say "Fair enough."

When I first saw Ia, I thought the tap ability was part of the first Loyalty ability. I wonder if that makes for a more interesting card? It couldn't be a powerful ability, true. Ia protects itself, but doesn't necessarily do anything for you, so that's why I thought it was okay. But maybe something like...

[+1] Add to your mana pool. Look at the second card of your library. You may put that card back, or put it on top of your library.

The mana is still restricted to sorcery speed, and it can still be knocked off the table like a planeswalker, so it still seems balanced to me. An alternative:

[+1] Add to your mana pool. You may only use this mana to cast creatures. Gain 1 life.

I don't know. I'm just spitballing.