Yeah, I added MetalGreymon and MetalTyrannomon because Commandramon, if you look at him, is just a grayish blue Agumon with some artillery, lol, and I figured it could give some alternate moves to the lines. Also mainly because I like how there are so many possibilities to get the same digimon(Similar to how Digimon World does things), which is why I added so many digimon to the line. I didn't wanna add EVERYTHING but I wanted to keep Darkdramon and since he said Tankmon and Deltamon(even though neither really come from Commandramon, they worked considering the megas). I also like the Gigadramon and Megadramon lines because they could easily replace Hagurumon, if he wanted to replace Hagurumon and for the DNA Digivolution, you could raise two Commandramons through different lines to get Milleniummon. If you could think of all the possible evolution methods for them, it'd be amazing to see them all on him, but if you'd prefer a simplistic line that's cool too. I'll go through the entire line just to give some ideas for possible evolution methods and you can use whichever of them you'd like to use:
I suggest Tankmon be the basic digivolution. Mainly because of the evolution paths I have for him are rather weaker seeming than the Deltamon path. Deltamon could be gotten maybe by holding an item when digivolving or possibly happiness below a certain number.
Tankmon to MetalGreymon possibly max happiness or a hold item, Tinmon normal(cuz it's one of the crap digivolutions, at least in my mind), MetalTyrannomon possibly low happiness.
MetalGreymon to Wargreymon normal, MetalGreymon to VictoryGreymon Atk or SP Atk depending on the stat he's gonna be based on above a certain number. MetalTyrannomon to Cannondramon normal, MetalTyrannomon to Machinedramon low happiness maybe?(I'm using low happiness as a way to get difficult digimon who are generally seen as evil because of how easy it is to have high happiness)
For Gigadramon and Megadramon I'm thinking maybe Gigadramon could be speed below a certain number, while Megadramon could be speed above a certain number, since Gigadramon is supposed to be stronger, but slower than Megadramon. Kimeramon normal.
Gigadramon to Machinedramon normal, Gigadramon to Darkdramon low happiness or some other slightly difficult evolution method. Megadramon to Machinedramon normal, Megadramon to Goldramon max happiness or some slightly difficult method(Leaning towards something different because of how easy happiness is to achieve, unless you make it more difficult to get). Kimeramon to Milleniummon either normal or DNA with Machinedramon(I suggest DNA with Machinedramon if you ever introduce DNA digivolution because then people will want to raise more than one Commandramon so they have both Machinedramon and Kimeramon, of course this is assuming you decide on using the full line I provided. If not then feel free to take ideas from whichever digivolution methods I mentioned for the line you want).