Hi folks

I'm doing my best to wrap my head around how 10th ed works, here. I've been thinking about a DG list for the end of the month, and I'm starting to doubt my own thought processes.
Am I an idiot for running a 10 man Plague Marine squad as a melee choice? Like, give em 4 heavy plague weapons, plus the champion gets a HPW, 3 get Bubotic weapons, and 2 get melta guns (because rhino drive-by), led by a CSM nurgle lord w. lightning claws (because thats what I have) and a Foul Blightspawn (again, thats what I have).
Is this likely to be effective? Or should I be running them as a shooty unit? Or two units of 5? It doesn't need to be optimal, per se, as long as it's not going to be a total bust in terms of effectiveness.
Thanks in advance for your thoughts
ps.
For context, in terms of what minis I have, I'm looking at:
more Plague Marines (I have about 14 painted actual PM minis, but I also have 10 or so unpainted PMs, 7 chosen, 7 havocs and 7 raptors, all very nurgly. I intend to just mix and match these as plague marines, until a better solution presents itself. Weapon wysiwg can go hang.)
poxwalkers (10 painted, 20 not)
cultists (like, infinity, unpainted)
blightlord termis (7)
deathshroud (3)
Assorted vehicles (mostly painted, but no MBHs or lawnmower-variant flying doohickeys. I do have a FW heavy plague drone, though)
Assorted leaders (The ones I dont have are: Lord of Virulence, Tallyman, Biologus Putrifier)
daemons (nurglings, PBs, BoN, soulgrinder)