Ok ! We have some more info and feedback from testing different boards and foils and teaching a few people how to foil!
Categories:it is now quite clear that different brands are taking a different approach to foiling:
1 High aspect foils = Technical/race
Brands like Starboard and Neil Pryde are catering for the "racing " side of the market with more high aspect foils or full on race foils. Due to the high aspect nature they require larger (racy) type sails and plenty of skill to get them planning in LOW winds. They are also a lot harder to Gybe. (planning through Gybes)
2. Medium aspect foils
Some other brands like Slingshot and Fanatic/North are bringing out medium aspect foils that have good top end but don't necessary require racy type sails. They will get planing easier in sub 10 knots conditions.
3 Low aspect foils
It looks like Naish is one of the only companies at the moment that is focusing on low aspect/very early planning foils. These will get planning from 6 knots and you only need a small wave sail. (4.7/5.3) these foils have still a surprisingly good top end but are not as fast as the more high aspect foils. These also are reasonably easy to Gybe.
So far, customer feedback tells us most people are interested to get foiling as early as possible using small sails.
Robby on 4.7 in 8-10 knots
Foiling specific boards:Ok this is really interesting, we are now starting to get some feedback from the "industry" that specific foiling boards are not necessarily an advantage. Think about it. To make a board more foiling friendly you have to soften the rails and make the bottom shape more forgiving. (potentially a wider tail) However this will impact the early planning of the board so it actually goes against getting foiling early. Foiling specific boards are also very average to sail normally. Once you know how to foil your board is out of the water for 90%of the time. So a foiling specific board is best for beginners only.
Most brands are now changing their normal Freeride/race boards to foiling ready boards (reinforce tuttle finbox)
A good example is the Starboard PWA team, all teamriders are using standard Isonic boards with reinforced box.
So no, you don't necessarily need a specific foiling board.

133 Starboard Freeformula with Slingshot foil and Starboard 120 AtomIQ with FoilMount and Naish Malolo foil
Adjustable foil set-upsMost brands will give you the option to upgrade your foil over time. You can get more high/low aspect windsurf parts or some brands will even allow you to crossover into other sports. Naish, Slingshot and Fanatic will offer mast, fusalage and wing upgrades for surfing, kiteboarding or wakefoiling.
What sail works best:We find that soft sails with 3/4 battens and lot's of pre shape work best to get planning (bag them out)
For higher speeds a sail like a Severne NCX will work quite well but you will still need to bag it out to get planning early
Here is a video of some of us learning in St Kilda, using a 133 Starboard Freeformula and Slingshot foil.
How does it feel:Initially it feels like windsurfing on a balance ball, once you are up and foiling you should use only very little movements other-wise the foil will take over and throw you off. It is easiest to have back strap inboard over the foil. Outside straps will make it faster but will make it feel like you are standing on the side of a balance ball. The higher the speeds the more stable it gets, once you are up and foiling you can try and pump through lulls using the sail on foil.
Safety:When learning we suggest you wear an impact vest and helmet. Also use booties as the foils can be sharp. Try to keep just above the surface to make touch downs easier to deal with. if you fly to high the foil will breach and will stop foiling = catapult !
More Info soon ! 
Starboard Freeformula and Slingshot foil