The 2015 Hobie parts and accessories catalog, page #35 shows a complete Elect connector set, P/N 72021027 for $20.
For an additional $1.60, you can order 4 ea, silicone grease filled wire nuts, P/N 72025005.
These parts will solve your second installation problem.
If it were me, I would just order another battery so I would not keep swapping the battery.....the battery should come with the connectors....just need additional inline fuse and AWG-18 leads, red & black to reach the fish finder........in my advanced age, I would surely take the PA-14 out, only to discover the battery is in the Outback
