I can't answer 2., but for 1.

• "Dick" was, and is, a nickname for "Richard", and as Richard is a common name it was used to mean "fellow, lad, man" in the 16th century. The usage of "dick" as slang for "an unpleasant person" comes from this original meaning of "dick" as "fellow", and dates back to at least 1665 ("Dick" as "penis" is originally army slang, from the 1880s):

The next Dick I pickt up for her was a man of a colour as contrary to the former, as light is to darkness, being swarthy; whose hair was as black as a sloe; middle statur'd, well set, both strong and active, a man so universally tryed, and so fruitfully successful, that there was hardly any female within ten miles gotten with child in hugger-mugger, but he was more than suspected to be Father of all the legitimate.

• "Cock" as slang for "penis" is very old, as it's attested in the 1610s. It might come from the Middle English word for "penis", "pillicock."

• "Titties" was originally a diminutive form of "teats." It dates back from at least 1746:

Come, be quite;--be quite, es zey, a grabbling o' wone's Tetties.---Es wont ha' ma Tetties a grabbled zo ; ner es wont be mullad and foulad. (this is Devonshire dialect)

Conclusion: Swear words have been around for much longer than we often think.

"Cunt" and "arse" and "shit" are in the Canterbury Tales. "And he grabbèd hire bī the queynte" would be the most famous line.

On dates

"Bloody" has been a swear word in Britain since the 17th Century.

"Shit" has been used to refer to dung and people in a derogatory way since the 16th Century.

"Poppycock" is a derivative of a Dutch phrase loosely meaning "bullshit" (in the literal sense). It's attested from the 19th Century.

"Fuck" has been around since the 16th Century at least and probably earlier.

"Cunt" is one of the oldest swearwords in the English language still in common use. The first written reference we have in English is from the 13th Century.

"Damn" existed as a swear word from the 14th Century, but in its own right before then.

Euphemisms were used as often as a way to get around censorship in historical times as they are now. Consider the following quote from Shakespeare's Romeo & Juliet:

ROMEO Why, then is my pump well flowered.

MERCUTIO Sure wit, follow me this jest now till thou hast worn out thy pump, that when the single sole of it is worn, the jest may remain, after the wearing solely singular.

"Pump" here is used as a euphemism for Romeo's penis. If you have a copy of Baz Luhrmann's Romeo + Juliet lying around, it's performed well, with the right gestures and emphasis in that. This is just one instance of a great deal of euphemism used by Shakespeare.

In Chaucer's 14th Century work, the Canterbury Tales he repeatedly uses the word "quient" or "queynte" as a euphemism for "cunt".

You might be interested in this history of English swearwords I wrote earlier.

While we are on the subject, what is the oldest reference to calling someone a chicken/hen/cock as an insult? The earliest I could find was 1400s.