(1) First of as a beginner it's advisable when choosing a wallet that you go for a hot wallet like metamask, coinbase etc over cold wallets. Though overall cold wallets are better than hot wallets as they are not internet based, making them less vulnerable to online hacks. So if later on you decide to diversify your assets, you can use the both hot and cold wallets. But if you're just starting, hot wallets would be advisable I'd recommend coinbase.
You recommend Coinbase? But hope not Coinbase custodial wallet nor exchange.
Metamask does not support bitcoin.
What you should first recommend nare cold wallets, they are the best, but it's wired that you know their benefit but recommending hot wallets over cold wallets, thatbis absurd and wrong.
(4) I know I made this thread specifically for bitcoin but how can you be a good investor if you don't expand your horizon. It's advisable to try out other Altcoins I'd recommend ethereum or ripple. Don't put all your eggs in one basket always research to see which coins are thriving well, check out their past and possible future, ask questions this is where those your sources come in.
In other words just try and choose your assets wisely.
Those that when for luna and ftt do not want to put their money in one basket nd they lost huge amount of money and regret what they did, just know that bitcoin is reliable and not disappointing like altcoins. But if anyone decides to just gamble with altcoins, it is not bad in bear time like this, but they should know that they are gambling and should be done with small amount which they can afford to lose.