Eh, I'm not particularly interested in a purely academic conversation.
There's no point in refrigerating sperm. When sperm is preserved for later use, it's done so at -196C. When it's used for at-home artificial insemination, it's recommended to be used "fresh," at room temperature, within an hour.
The withdrawal method CAN and does result in pregnancy, since pre-ejaculate contains sperm and would be deposited near the cervix. Handjob with sperm isn't viable because there's no real way to get enough ejaculate on a hand and up to the cervix - the same reason ejaculating outside of the vagina isn't a risk. Sperm don't "crawl" up a vagina and into the cervix.
Since the MedHelp forums are intended to help people with actual medical issues they are experiencing, rather than for the discussion of theoretical issues, I'll stop here to avoid derailing the purposes of these forums and leave speculative conversations for venues such as Reddit (where at least one person will always tell you a theoretical possibility is a realistic possibility).
I will probably regret asking this, but why is someone keeping sperm in a refrigerator?
The only realistic way for a woman to become pregnant is by inserting a penis into a vagina. Any other method you think of (outside of a fertility clinic) is not realistic.