I propose the robotic mega surfboard solution. I really hope someone builds this, but it won't be me. I started looking into it and was amazed at how doable an electric version of your product will be, but for the full effect it won't be cheap.
Surfboards vary in size and this one will have a bit of extra weight and it may have limitations in use for pro surfers, but if you've got a lot of money or a sponsor or something and you know how to build surfboards, I think a minimum 6'8", 19.5" board is in order.
It will have a top side surface area of roughly
83% * 2.032m * 0.495m = 0.8474m\$^2\$
which will give you space for roughly 22 1.54W flexible 15.4V military grade solar panels. That will bring in 33.88W in bright sunlight at a cost of about $1000 (less in american), but only adding 312g plus wiring. Even when you're surfing the parts of your board with no shadow will generate power. I believe measures should be taken if possible to spread the heat from the cells, perhaps share it with the bottom side with an internal water loop because many of the mini jet motors available appear to have engine cooling anyway. A flexible aluminum mesh behind the panels and following the interior curve of the board and several thin aluminum plates on the bottom surface might be in order. You could get away without it, but a bit of reinforcement and also heatspreading for the other components could be in order anyway. Blackish things get pretty hot in sunlight and the better it sheds heat the more power you'll get from your panels.
Water thrusters won't clobber people as bad as a propeller, so I think they're the way to go too, and looking at the options available, perhaps a pair of 40mm pumps placed on each side and angled slightly outward are in order, intakes facing down so they're not blasting down the middle where you are.
If they don't come with the thruster pump heads, perhaps 2 250W RC motors, allow 1lb per motor and pump assembly with motor driver and add 1 lb total extra for heatsinking. If weights start getting too high it may be necessary to add voids and/or use materials like carbon fibre tube, sheet and cloth to reinforce the board and increase buoyancy.
You'll want some power storage, maybe up front to help balance the weight in back? A decent size Lithium ion battery bank will cost probably $200 or even $400, and the larger the battery bank the less the batteries will heat up at a given power draw. Perhaps augment it with a substantial sized capacitor bank to take in power from the solar and provide burst power for the motors. If the capacitor bank is below the voltage the motors can sustain continuously, have the batteries charge it, and if the voltage is close to the maximum the panels can put out, instead have the batteries take a charge from the capacitor bank. This way you'll always have a mimimum amount of thrust that won't cook your board until the battery bank runs out, and while you're in the sun the board will constantly be preparing for the next boost of thrust and charging the battery bank with remaining energy.
Wireless charging would work fine too so feel free to add that.
All told you can probably squeeze this in under 4 pounds with existing factory made parts and add just the right amount of buoyancy while you're at it. Perhaps instead of a wood spine a hollow aluminum heatpipe would work.