Bitcoin will not get affected even though they will launched Libra successfully. just like XRP when they introduced it to us, they say, we will forget the use of bitcoin if it launched. now look what happen, XRP will be soon forgotten. Judging with pay pal leaving the partnership with Libra, there's no other explanation with it if not pay pal realize this Libra project is nothing like bitcoin. like the other altcoins, it will only blooms on his premiere, days will past it will soon forgotten. this is my opinion regarding your questions.
The libra is a stable coin, so Bitcoin will suffer. Bitcoin will take most of the liquidity in the cryptocurrency market and beyond. Libra, in fact, is a new generation of USDT.