Originally Posted by SPlDER

For first 3 question answer is yes.

If you are thinking about switching from M&M then disadvantages are earning rates.
- no miles cheap booking classes on LH (including P business class)
- only min. 250 miles for most middle-cost economy class :Q, V, S, W, T
- no privileges and lounge access on Air Dolomiti, Eurowings/Germanwings
- extremely bad earning ratio on business and first class
- no exec. bonus

IMHO talking into account earning ratio getting gold on United may be easier. Other adv.:
-UA miles are much useful (no YQ)
- 25% exec bonus on LH/UA flights