3. Yes. Mix through altcoins is a third way, which I had not organize and describe here yet. (I am engaged in this now). This way has some advantages (my thoughts about them I will write later) and a some minuses. One of them is that this way is, in fact, too complicated and you need to press "a lot of buttons."
In your case, you must register monero purse. Load btc to exchanger. Exchange btc to monero and then move them back into Bitcoin. As for the fees, they are quite acceptable. I looked through the shapeshift
Instant Rate 1 BTC = 96.4909903 XMR
Instant Rate 1 XMR = 0.01020749 BTC
Miner Fee: 0.02 XMR
That is for 1 btc the output we get: 0.9849. So the commission will be 1.5%. It`s acceptable, isn`t it? However, the extremely small size of the market spoils everything.
Good calculation, yes 1.5% is acceptable and also i don't think market size is small for monero if you don't want to mix 100s of bitcoin in one attempt. Shapeshift seems to have max 1.96115039 BTC in bitcoin to monero direction so it will be enough to mix <1
BTC.
Gambling sites will not provide reliable mixing and the bitcoin you may receive from them can have some taints.
In addition, I would say just the opposite - the less legitimate site is the more suitable for the mix it is, I mean that there are low chances that site will share logs or has logs at all. i.e the less the site is legitimate, the more it will be similar to the site of the first group.
True, but using less legitimate site increases risk of lossing all you have deposited there because even if they run away or doesn't allow you to withdraw there will be no place to complain about them.