Incorrectly reciting the Quraan Majeed

Q: When I recite Quraan, whether looking inside or not, if I dont know the correct pronunciation of a word or I don't know what the next word is, I guess what it is and continue in that way. I feel lazy to check the correct word or its pronunciation even though I have a Qur'an near me.

Also, sometimes when I read Qur'an while looking inside, I guess the next ayah or the continuation of same ayah because I feel that I know it or I have heard or read a similar ayah somewhere. I don't read a word wrong while knowing the correct pronunciation.

Is this the same case as adding or removing a word or letter?

Spaying a cat

Q: I have a female cat. Many people told me, including my cat doctor to get her spayed (spayed is a surgery to remove female cat uterus and ovaries to prevent her giving birth). My cat doctor told me spayed has many benefits (including health benefits because many female cat got cancerous cells after giving birth to lots of kitten and also less population so kittens cant roam homeless and starve on street also female cat will have less risk to get lost or injured in a traffic accident in searching of a mate which is because female cat dont go on a heat after spayed). My question is! Does Islam allow us to do female cat spayed? Is that haram?

Sweat of a kaafir

Q: I read that the sweat of a kaafir is impure. In the Uk there are lots of shopping centres where the cashiers are non Muslims. If we go to the cashier with our food or clothes and they touch it to scan it are we not allowed to wear those clothes and eat that food?

Binaa

Q: What is the procedure of doing binaa in salaat? Do you have to go back to the same place in Haram or is it ok to read from anywhere in the Haram once you have redone your wudhu.

And how do you rejoin the salat, in which rakaat etc in the situation where the imam has already finished?