Kevin, tough to comment on the value of the Alpine. These cars tend to rust out from underneath and are difficult to repair as they do not have a separate body and frame. Poke around the underside of the car in the area of the rocker panels. Also the front inner fender panel just to the rear of the tires. Also check inside the trunk, in the front corners. These will give you a good clue as to the soundness of the body. BTW, where are you located? That has a lot to do with the soundness of the body.
The German Pinto engine is a good engine, very sound and can take tons of abuse if you are so inclined. The weak link is the head. Valve train (cam bearings and cam followers) is prone to early wear and the valve ports look like they were designed to limit power. But they were the engine used in the Formula 2000 cars for about 30 years, so all is not doom and gloom.
The outlook for transmissions is not good. Ford never bothered to import a 5 speed tranny for this engine. The available four speeds are adequate, not much more. The worst part is lack of the overdrive 5th gear, especially as the Alpines had 3.89 and 4.10 rears. The Ford T9, by all I've ever heard a fine transmission, is widely available for this engine, but you'll have to go "over there" to get one. Ford Ranger transmissions almost fit, the latest examples seem to be okay. The pre 1988 examples have bad ratios. If you decide to use a Ranger, you will find that only four of the 6 bolts line up and you will need special pins to align the transmission to the block. That is no big deal and should not be a part of your decission. If you decide to go that way, I'll make them for you. But the clutch, starter, etc. are all compatible.
Ooops! Just realized the distributor location of the Kent engine is the same as the German Pinto. Is this engine an over head cam with a belt cam drive? If not, it is a Kent engine and little of the above applies.