Can you help check my design for this remote light?

[Jono427]

I could use some help with some questions and any other advice for the design or tips for the schematic.

Run down of the parts:
The encoder/decoder uses the 8 switch module for an address, the decoder will only process the data if it matches.
The 4 switch module is for the "data" being sent.  You can either send a low or high (5v in this setup) and this will trigger the LED array MOSFET.  I'm using the data so you can activate up too 4 different lights independently but also at the same time (same address on receiver but set one to '0001' and '0010' to activate the MOSFET).


Docs:

MOSFET
http://www.onsemi.com/pub/Collateral/FDU3N40-D.pdf

HT-12D (Decoder)
http://www.holtek.com.tw/documents/10179/116711/2_12dv120.pdf

HT-12E (Encoder)
http://www.holtek.com.tw/documents/10179/116711/2_12ev120.pdf


Questions:
1 - How should I manually activate the light?  Will the way on the schematic work or is it better to have the switch parallel to the MOSFET and switch the power directly?

2 - Which side of the battery should the power switch go?  I see lots of conflicting info about it being on either side for different applications.