Coming from an ex Football and Rugby player I would say that using metal studs would be a horrendous idea for woodsball. They're great in soft grass in which they can stick into however, as soon as you step on any sort of decently hard surface (step over a tree root, inside a base etc.) it can be like walking on sheet ice. The other problem with Football boots is that as they have gotten lighter and lighter they are not incredibly durable, over the years I saw a good 6 or 7 people using Nike Vapours which ripped during a Football game! So yeah I would not recommend those for Woodsball. What I would recommend is using a pair of tougher (but heavier) boots with moulded blades on the bottom, preferably rugby boots in my opinion (made to be rugged). These will give better traction across all the different surfaces you will encounter.
In terms of speedball I think any type of Football/Rugby boot will work so long as you play on grass/thick astro turf, so just look for a pair that feels best for you. Check out any decent high street sports shop and they'll have a selection.
Finally if you do get a pair of Footy/Rugby boots consider getting ankle protection or at least be aware of the surfaces you are running on and be aware of trip hazards. Twisting ankles can happen if you are not aware