In my opinion, some of the implemented gadgets for the april fools update has some sort of relation to the current 1.10 update which has been confirmed to be in development. Here is my analysis:

Ankle Monitor:

If you have noticed, the Ankle Monitor gives out a slowness effect when worn: but in Vanilla Minecraft, this can only be achieved by modifying the attributes using command blocks. This code may be reused in order to have some sort of item that when worn gives some sort of negative or positive effect. I think this may be tied to some treasure armor but I may be way too off from my suggestion.

Smarter Watch:

This is the first time we see statistics being displayed in chat, upon getting to a certain threshold. In the future, we may be able to allow statistics to be shown in chat via command blocks upon reaching certain thresholds. We may also have some sort of new tied achievements but I'm too far off. We may have also some sort of text that updates every certain amount of ticks and that can be found above the Exp bar. In the update, it nearly takes the place of just selected objects (ex. "Diamond Sword" in Slot 1 when selected from previously selected Slot 2.)

Reality Vision:

Now this is the most interesting because it contains too much effort from Mojang for just this simple object. It is the first time we see full 3d rendering of loading chunks inside a world. We have maps but each block only corresponds to a certain hex color which is put in the map. In this item, the y-axis is also considered which I find very interesting.

Also, about the "obey" sign, I think this may be tied to some sort of secret passageway or hidden area which can be accessible by using a certain object, in which changes the texture of the current block client-side. This is the first time we see blocks changing only client-side when doing a certain action (ex. wearing the helmet).

Signs

I just think of some sort of new texture for the signs because having wooden signs in a quartz area does not fit in. This may be related to the recently implemented igloos where the wooden sign texture does not fit with the room at all.

Hopefully that's all the things I considered interesting the April Fools Update and that some parts of the update are already being developed in 1.10. It may be just me, but this snapshot is just a teaserof what is yet to come, even if we don't know what the current theme is.