I am not considering legal issues here, because it depends on which country you want to host your page, and even if it is not possible, you can still do a crypto to crypto page, which is not regulated.
In Op's case,I believe they don't want a crypto-to-crypto rather USD to BTC as mentioned clearly.So yes,legal issues still be a concern if they do it openly with their IP's and accounts registered with that country.
isnt and easy task, having a site with these pourposes would be very complicated, first thing is that for any that wants to buy bitcoins once the btc deposit is made that person can roll back the payment made by card, there are other complications
And your point again ? If you're done with sig spamming the project development section..please..