So I am making a shield that give bonus HP to a character. 

The drawback is that healing abilities and spells only work at 50% and no hp are gained during rest periods.

I know how to grant the HP bonus but then other then using text to create the disadvantages is there a way to do all these effects inside the toolset?

Also I did bonus HP in the options with a set value and they are not transposing to the character sheet when the shield is equipped and attuned.

How would this get fixed?

It's a shame you can't just add resistance to healing. That would do the trick.