The older Mr. Beer fermenters were designed to have a short piece of hose go over the spigot, and then onto a bottling wand. That allowed a longer piece of hose to be used and the wand to be moved around a lot.
My batch priming process uses a 2.5 gallon slimline from Walmart. The bottling wand fits into the spigot (which is very similar to the new Mr. Beer spigots), in fact you have to take a drill bit and turn it by hand in a new spigot to get it a tad bigger (and then wash and sanitize the spigot). Rarely does it fall out.
The newer fermenters are designed for the wand to go inside as noted. If your bottling wand slips out, then the solution (beyond taping) would be to take the spigot and wand to your local hardware store (making sure they sell food grade tubing by the foot - Lowe's and Home Depot only sell 10 foot lengths now). Get a section of hose that fits into the spigot, and then play around with hoses to go over the bottling wand, and connect them with an adapter to the piece of hose in the spigot. Use hose clamps to hold the pieces of hose together. Not pretty, but it won't undo as easily.
You want to pour the first half of the bottle down the side of the glass, and the second half right into the middle of the beer, generating whatever head it can. In general, Mr. Beer recipes don't generate much head unless you steep some carapils (when you start steeping grains), or wheat, or add some wheat LME/DME. Make sure you leave the last bit in the bottle, as it gets cloudy during the pour you want to stop pouring.
Make sure the conditioning and carbonation takes place at 70 or above for 4 weeks.
The recipe builders can give indication of the yeast attenuation when you select the yeast. I found it interesting to see the variations on FG. But it will also affect residual sweetness.
Look at the range, from a saison or champagne yeast at 90%, to ale yeasts at 70%.
The "Cry Havoc" liquid yeast gives pretty sweet/malty result and you can use it for ales and lagers too.