a-> You can get the Text for tweets by post processing the data returned from twitter api.
In[3]:= twitter = ServiceConnect["Twitter", "New"]
Out[3]= ServiceObject["Twitter",
"ID" -> "connection-daaea6b1e90f6335cc7d7da583b4899c"]
In[38]:= res =
twitter["TweetList", MaxItems -> 2, "Username" -> "elonmusk"]
Out[38]= Dataset[ <> ]
In[39]:= (res[#]["Text"]) & /@ Range[res // Length]
Out[39]= {"RT @SpaceX: Successful deployment of SES-12 to a \
geostationary transfer orbit confirmed.", "RT @SpaceX: Falcon 9 and \
SES-12 went vertical this morning on Pad 40 in Florida. Weather is \
70% favorable for the four-hour launch window w\[Ellipsis]"}
b-> TweetSearch do not support querying text based tweets for a specific user.
c-> Tweets > 140 characters are supported.
In[42]:= ans1 =
ServiceExecute[twitter, "GetTweet",
"TweetID" -> 951803393345015808][["Text"]]
StringLength[ans1]
Out[42]= "@Raspberry_Pi @MakeUseOf I put up my first Raspberry Pi \
twitter bot earlier this week. It plays the game \
\[OpenCurlyDoubleQuote]24s\[CloseCurlyDoubleQuote] over Twitter. \
Written in Wolfram Language because why not? \[LongDash] 2, 5, 5, 6 \
#24sTest"
Out[43]= 191