Internal Sounders better to fit separately imo , out of reach ,and o e right outside your bed room
When it goes off , you jump out of bed like a lunatic and the kids needs a nappy change
Ricochet can habe it's difficulties to setup , although those that install it regular have less issues
Also with respect, if majority sensors are wired , cost of a hybrid system now is better , but seems you missed the point
Ok so keep everything that is wired wired and then add wireless units where needed if you can't get cables there or are lazy
So you need a slightly different panel that gives you more wired zones or expander wired for panel your thinking
Not sure which expander tho , ask an expert lol
Surface , buy all the bits for it and you need good budget
I tried a Samsung Tab , gave up and use my head now lol have it to one of the kids to use ( tax perk?)
House bashers R us
Yes there are some right Muppets when installing bells
Then customers become Muppets aswell when they want it high like the Muppet neighbours
External bell boxes mostly ignored when they gain access from rear and no internal sounder fitted ......
Replace cover while your at it if it doesn't clean up well , but as swb says , battery cheap to replace
Chop that bad boy out and put a new battery in if your capable