Can't answer the Morning Star question. I would not worry about detachable antenna on the Myfi. I'd consider a signal booster. Verizon devices are capped at .25 watt output. The Wilson Sleek is about 1.8 watts. The next step is more expensive. The Wilson Mobile Pro 4G is also more powerful and universal. The Mobile Pro 4G has an advertised 5ft range. This is being generous. I would place the Myfi directly on or next to the internal antenna.
The Mobile Pro 4G is good for 5 device. I've only tested with 2 at the same time. The Sleek is good for about 18db gain. The Mobile Pro is advertised at 50db gain. I average 35db gain.
Wilson SleekMobile Pro 4G