I could try to help sometime soon, best bet till I can I would say to look up some reference on google image search unless you've done so already.

The issue is, everyone's views of a manticore varies vastly. I have looked into Google images once before I started the sketch several weeks ago... but maybe another look is in order.

That is true, I did forget about the wide range of variety there. For a creature that is drawn so differently by everyone I'd say do what you think is best for you character. Just the same as people draw anthros, I myself prefer making them more animal like and give them the digigrade feet and more paw like hands along with their humanoid body and charactistics to keep a more fine balance between the mix, unless of course the character is supposed to have plantigrade then I kind of have to force myself to draw that in lol.

Either way though, really it is up to the creator ultimately!

I would love to do digigrade legs but that would be difficult with a muscular character.

It's not too hard, there are tutorials I think around if you need them but it's all about proportioning, remember the thigh will be normal and as you ascent lower to just make the limbs thinner, generally around the ankles and feet it gets pretty thin, but I'm sure you'll figure out something!

Smaller hands and maybe a marking/tattoo on the tail

Big hands is just my style.

I guess the hand could use some shrinking now that I look at it. Tattoo sounds like a good idea!

n.n; glad to help

He could probably use some clothes... That is, unless you don't want them. XD

Well, for this picture I wasn't planning on clothing.

With something so far into mythology as a manticore, you might add some weird designs to the fur.. either painted or glowy magical things.

Also: horns. Try some horns. I'm thinking ram's, but that's just a personal preference.

Ooo those are some wonderful suggestions! I may add those one I color him :3