Chances are, these answers are obvious but for whatever reason I just missed them or whatever.

1:Voice control is not the only to navigate menus is it? I saw someone ask the question "what if the person can't speak?"

no one "knows" but it would seem safe to assume there are other ways to navigate the menus.

2: What exactly was the point of adding a heartrate monitor to the system and how exactly does it work?
I love the muscle stress thing. But the Heartrate thing does seem to be taking it a step too far, maybe it's just me but that is my biggest discomfort with the One.

i imagine this is an idea that came about in part because of nintendo's vitality sensor so that MS could support all those great ideas nintendo came up with for knowing a heartrate.  ..assuming good ideas ever existed.  maybe MS will monitor your heartrate an call an ambulance if you have a heart attack.  ..or show you an ad for an ambulance service.

3. From my understanding (please correct if wrong): Disc games install once to your system and then can be played from the system without the disc. The question is; If that's the case, won't it be easier for me to just buy the game from XBL and cut out the middle man?

basically xbox is following a digital distribution model only.  the one questions is do you download from the internet or do you download from a disc.  for big games (file size) a lot of people will need a disc based download to get the game in a reasonable time frame.

3b. There's so many things out there about used games on the One that it's hard to get any sense from it. Assuming the above is true, does this mean that a scenario could happen where you buy a pre-used disc from GAME (or whereever) for say... £10, take it home but can't use it because the system wants you to pay the full £40 that's the original asking price. so technically, there's a situation where you end up spending more for a 2nd hand copy of a game than you would the first hand. Which I guess is just the same as the question in 3A. Would it be easier to just cut out the middle man and buy from XBL?

i'm not quite sure why everyone is confused here but...

you buy a disc and you put it in your system and that game gets tied directly to your account.  from there two seperate things could happen.

A) you just hand that disc over to a friend.  your friend can't play the game because the game license is tied to your account.  however, your friend can download the game data to their system and pay for (at full price) a new game licence from xbl.  basically this saves your friend the trouble of having more packaging to throw away.

B) you take your game to a MS certified used game dealer with an approved MS Azure server.  that server then reads the game disc and deletes the license from your account on xbl.  at that point the disc can be sold as if it were new to someone else and there will be no additional fee for whomever buys the disc when they install it on their system. 

for you, MS's "frequently online" infrastruture will connect to your system and remove your ability to play the game you had installed on your harddrive unless you buy a new license.  if you aren't connected to the internet (so that MS can decide if you have permission to play your game) for more than 24 hours your system will remove your rights to use any of your xbox content (other than blu-ray discs) until you reconnect to the internet.  this is basically there to ensure you cannot install tons of games on your system, disconnect from the internet, sell your game, and then keep playing your original install.

so yes, sorta, the second hand copy costing more situation probably will happen to "suckers".  bascially i can almost gaurentee someone will convience someone else to pay for a disc that has a licensed tied to someone elses account.  the cheaters and scammers are going to make a lot of money on this plan especially considering how much confusion there currently is.  the whole system is too complicated for the average consumer.

Chances are, these answers are obvious but for whatever reason I just missed them or whatever.

1:Voice control is not the only to navigate menus is it? I saw someone ask the question "what if the person can't speak?"
Certainly not. Hand gestures and/or controller should do it.

2: What exactly was the point of adding a heartrate monitor to the system and how exactly does it work?
I love the muscle stress thing. But the Heartrate thing does seem to be taking it a step too far, maybe it's just me but that is my biggest discomfort with the One.
I heard the Kinect uses the IR to see your puls rate through your carotid artery or other veins or something like that. I'm not one hundret percent sure either here.
It will definitely be used in sports (and I'm not talking about FIFA >.> ) and fitness games.

3. From my understanding (please correct if wrong): Disc games install once to your system and then can be played from the system without the disc. The question is; If that's the case, won't it be easier for me to just buy the game from XBL and cut out the middle man?
MS will make sure that you have to pay the same price regardless :P
The games will get even bigger, so if you have a very fast internet connection it might be better for you.
Though the first SKU has "only" 500GB of HDD space, so if we assume an average of ~25GB per game (which is probably a bit too high for the first few games), you'd need to deinstall a game after you have 20 on the HDD. That's where the disc might come in handy again.

3b. There's so many things out there about used games on the One that it's hard to get any sense from it. Assuming the above is true, does this mean that a scenario could happen where you buy a pre-used disc from GAME (or whereever) for say... £10, take it home but can't use it because the system wants you to pay the full £40 that's the original asking price. so technically, there's a situation where you end up spending more for a 2nd hand copy of a game than you would the first hand. Which I guess is just the same as the question in 3A. Would it be easier to just cut out the middle man and buy from XBL?
From what I've read there is no unified answer from Microsoft on that topic, so I can't answer that.

Chances are, these answers are obvious but for whatever reason I just missed them or whatever.

1:Voice control is not the only to navigate menus is it? I saw someone ask the question "what if the person can't speak?"

2: What exactly was the point of adding a heartrate monitor to the system and how exactly does it work?
I love the muscle stress thing. But the Heartrate thing does seem to be taking it a step too far, maybe it's just me but that is my biggest discomfort with the One.

3. From my understanding (please correct if wrong): Disc games install once to your system and then can be played from the system without the disc. The question is; If that's the case, won't it be easier for me to just buy the game from XBL and cut out the middle man?

3b. There's so many things out there about used games on the One that it's hard to get any sense from it. Assuming the above is true, does this mean that a scenario could happen where you buy a pre-used disc from GAME (or whereever) for say... £10, take it home but can't use it because the system wants you to pay the full £40 that's the original asking price. so technically, there's a situation where you end up spending more for a 2nd hand copy of a game than you would the first hand. Which I guess is just the same as the question in 3A. Would it be easier to just cut out the middle man and buy from XBL?