Kissing one's wife while fasting

Q: Regarding kissing the wife during Ramadhan fast. I knew that it was permissibile to kiss the wife as long as it does not lead to anything further. Only recently did I become aware that only kissing without the tongue was meant as kissing with the tongue would require qadha and kafaarah due to the exchange of saliva. As kissing with the tongue is the norm I had not made that distinction till now. Am I required to perfrom qadha and kafaarah or just qadha due to misunderstanding as I see in nurul idha that kafaarah will not be required if someone misunderstood the hadith?

Working for a company that prepares software for banks

Q: I am a software engineer, currently working in a software house, I wanted to switch my job and later on I got a job in a very nice & reputable company. But they worked for banks, basically they are a banking solution provider, I know this thing from the very first day, but due to the lack of my knowledge, I was assuming that working in banks is impermissible and as I will not be going to work in a bank that's why I didn't bother. But when I got the offer letter, I did Istakhara. I did not see anything in my dream or I didn't get the clear picture of what I should do, then I searched on the Internet that what Islam says regarding this issue. I've found in many places that its forbidden to work
for bank or work for such companies who gain their profits from banks, so I refused.

I wanted to know that is it allowed in Islam to work for such companies that help banks? Keeping this in mind that I didn't know at the time of refusal that what kind of software they were requiring me to make.