Who could be a potential fit for the next Doctor if it were played by a non-white actor?
Considering that the doctor has never been played by an actor of any color but white, this is a very interesting question. Truth be told, Timelords themselves are normally white with very few exceptions as well. I think the series has made huge strides to fight against preconceived notions and stereotypes in the modern run since 2005. There have been numerous LGBT characters and people in unconventional roles for their race in historical contexts as well. Often they will have strong actors of color taking roles you might not expect in historical contexts. The creators have certainly not ruled out the idea of an actor of color or having a woman for the doctor. They have considered this possibility a few times recently.Colin Salmon was considered as a possible candidate for The Doctor as was Paterson Joseph previously. Of those two I think Joseph might be a bit too quirky for the role and Salmon possibly too serious. A good Doctor needs to be able to be scary serious and decidedly quirky. Richard Ayoade as suggested in the question details might also be a good choice if he can find the right balance. An Asian or middle eastern actor could also be as good in this role as any other race. The Doctor is a very unusual character and not an easy one to play. It is more about the combination of comedic timing and making the outlandish stories seem believable than it is about anything else. That can be a hard balance to maintain as the stories often go from silly to serious from scene to scene. I think if they did go for a non white actor they might choose someone of mixed racial heritage to try and make the choice less shocking to those not ready for such a bold change. I myself, would welcome an actor of any race or gender that can balance the serious and funny as I expressed above. Change is hard but it can be the best thing to liven something up.
Do the actors that play The Doctor on Doctor Who get to pick their character's clothes?
Occasionally. The first four Doctors were entirely decided upon by the production team. Jon Pertwee (The Third Doctor) wanted to wear a modern-day suit but the producers disagreed, although he later admitted that he was quite fond of his new costume. Tom Baker's (The Fourth Doctor) costume was decided on for him but there is an interesting story regarding the famous scarf. A short striped scarf was originally decided on and they gave the costume-maker a large portion of wool in order to make it. To their surprise, the costume-maker used ALL the wool. Despite the mistake, the producers loved it and Tom Baker insisted upon it. Peter Davison (The Fifth Doctor) suggested a cricket jumper but apart from that, his costume was decided for him. The most extreme case of the actor's thoughts being totally dismissed occurs in the case of The Sixth Doctor (Colin Baker) who wanted something he would describe later as "not dissimilar to what Christopher Eccleston (The Ninth Doctor) wore". Instead, of course, he was lumbered with the multi-coloured monstrosity he eventually wore. The Seventh Doctor (Sylvester McCoy) again had his costume decided for him but the umbrella was his suggestion. The Eighth Doctor (Paul McGann) again had no say in his costume and greatly objected to the wig. The Ninth Doctor (Eccleston) was asked for what he'd like to wear and replied that he didn't mind as long he wasn't wearing "something silly". The Tenth Doctor (David Tennant) said he wanted a long coat and was allowed to choose his costume from a large collection of garments. The Eleventh Doctor (Matt Smith) was also allowed to pick his own clothes but producer, Steven Moffat strongly disagreed with his choice to have a bow tie but Smith insisted. Moffat later admitted that the bow tie was a strong part of The Eleventh Doctor's character. Bringing us bang up to date is The Twelfth Doctor (Peter Capaldi) who was allowed to completely choose his own costume.
How often do they switch main characters in Dr Who?
Having Doctor Who regenerate into a whole new doctor has been an integral part of the series since its earliest days in the 1960s. From a story point of view it is a good thing because it keeps the series fresh and new. From a production point of view it is necessary because eventually actors move on to other projects while the TV series continues on. Most actors play the role of the Doctor for about 3 seasons before moving on. Sometimes they stay longer. It depends on their contract and what negotiations are made. The longest time one person has continued in the role was when Tom Baker played the fourth Doctor for seven years in the 1970s and 1980s. The Shortest time was for a single story when Paul McGann played the eighth doctor in Doctor Who - the Movie, shown in the years between the classic and new series. To date there have been eleven doctors. While the actors and personalities can change quite wildly, there are traits and ideas that are consistent across all the doctors. The more you watch the show the more you will also pick out mannerisms and styles borrowed from older doctors and used by later ones. The main thing is that Doctor Who is a continually evolving and changing story. It is because it brings in fresh ideas and new blood that the show has become one of the longest running science fiction shows in the world. Stick with it, the new doctors do grow on you, and it is always interesting to see their take on playing the role.
Do you like or hate Peter Capaldi as the new Doctor Who?
I have watched Doctor Who for more years than I care to remember. Have to say since Capaldi took over the role I wont be watching again. Got my DVDs & old tapes to watch.
Why did the change Kate's character in pretty little liars?
Well, first of all, they want an actor who should fit the character. When they picked Kate, they picked her for only one time. And I just can't imagine THAT Kate being vicious and evil-minded. And Jason - he didn't seem to me like Ali's brother. And the new actor - well, he seems more like Ali. It's all about fiting the character.