Door Latch kids (double) safety

My young boy (1 year old) was getting closer and closer from being able to unlatch the downstairs door.

I was kind of worried, so a morning I decided to (very) quickly design this double security for the door latch.

The design is not bad, but could be better. I was quite in a hurry.

I would like, first, to make sure it isn't possible to remove the elastic.
Secondly, It is kind of getting annoying to have to push back on my device to "re-latch" the door. Maybe a pivoting portion (or co