It will get crowded soon, but should be ok right now. It's a dangerous game you're playing though. Just make sure that you really do upgrade that tank soon.
Also, don't Elephant's like to hang out in groups? I've always seen them packed together in a pretty tight school (even touching each other) - even at feeding time.
Are you going to move everything from one tank to the other, or just some fish? If just some fish then maybe you can just move the Elephant and Angels and then get the elephant 2 or 3 friends.
The pregnant guppy isn't a concern. Everything in that tank will goble up those fry.