Again, you're welcome - I hope it all goes well, to your satisfaction. Are we perhaps eventually going to get to see some piccies of this masterpiece?!
I think there's probably a lesson to be learned here by all of us. Had you told us at the start exactly what it was that you wanted to do (rather than asking specifically about tiny 18-pin plugs/sockets), I think we would have got to the same conclusions in far less than 5 pages - certainly in terms of the fairly dramatic reduction in number of pins/wires, and at least pointing out to you (maybe 'for future reference') the general undesirability of unnecessarily using plugs/sockets of any sort when one wants a high degree of protection against water ingress.
Kind Regards, John