1. Bitcoin is Digital Cash

2. Bitcoin can be sent in 10 minutes depending on how many sats you pay as the fee, it can take anywhere between 10 minutes to a day, or longer, with the modern memepol you can accelerate this luckily, in the past this wasn't the case.

3. That's called fungibility, and depends on who you ask, and the ethos, cypherpunks might say Bitcoins are Bitcoins but for investors they would not want a Bitcoin that could be traced back to Darknet Markets as Centralized Exchanges might reject them, or hold them indefinitely, Bitcoins that might cause issues are typically referred to as "Tainted Bitcoin", & can be caused when using coin mixers as Exchanges typically flag coin mixing.

4. You can fake Bitcoin through Double Spend, and inflation bugs, in 2010 such a thing was exploited (but reverted) however nowadays, it's unlikely for either to occur since the code has been updated to reduce/prevent either from happening.

5. Yes, the consensus of the current network says that Bitcoin's cap is 21 Million, however this can be changed at any time with forks.