Core Rules
No
From the spell description p. 283
If you turn a creature into another kind of creature, the new form can be any kind you choose whose challenge rating is equal to or less than the target’s (or its level, if the target doesn’t have a challenge rating)
It explicitly states that creatures without challenge ratings have levels. This implies that creatures with levels do not have challenge ratings.
The spell only allows you to turn the target into a creature with a challenge rating - not a creature with levels.
For example, you can choose any of the humans in the monster manual, the priest, the assassin, the archmage etc. but you cannot choose a Human Wizard Level 19 because this creature has no challenge rating.
Optional Rules
Yes, but its not straightforward.
From p. 283 of the DMG for NPCs and Monsters with Classes respectively:
... then determine the NPC's challenge rating just as you would
for a monster.
You'll need to recalculate its challenge rating as though you had
designed the monster from scratch.
The older edition paradigm of CR=Level does not hold true in 5e.
It would take some considerable time to determine the CR of you Kobold + Wizard level monster and is likely to bog the game down dramatically if it happens during a session. If this is something that you want, I suggest the DM and the wizard decide on a few "go to" polymorphs and work them out in advance.
This appears to be how the Monster Manual Appendix B NPCs were assigned their CR.
The key word in the rake description is "typically." So rake says
A creature with this special attack gains extra natural attacks under certain conditions, typically when it grapples its foe.
It then goes on to tell you how the ability works under the typical conditions:
In addition to the options available to all grapplers, a monster with the rake ability gains two free claw attacks that it can use only against a grappled foe. The bonus and damage caused by these attacks is included in the creature’s description.
Finally, there is a limitation placed on using the rake ability in these typical conditions:
A monster with the rake ability must begin its turn already grappling to use its rake—it can’t begin a grapple and rake in the same turn.
But then we have pounce, which grants a specific exception:
When a creature with this special attack makes a charge, it can make a full attack (including rake attacks if the creature also has the rake ability).
Specific trumps general, so the extra attacks from a rake can be used when pouncing.
Best Answer
Seeming will not work to make a dire wolf appear as an orc
This part of the spell means that while in wild shape the druid will not be able to take advantage of the illusion of being an orc since the dire wolf does not have the same basic arrangements of limbs (the wolf being a quadruped versus the orc being a biped).
Even if they did have the same arrangement of limbs, transforming from a large direwolf to a medium orc would definitely be considerably more than 1 foot of height difference and arguably would exceed the extent appearing fatter or thinner as well.
If you had using seeming after wild shape to create an illusion that the druid was another type of creature with the same basic arrangement of limbs then it would work while the druid was still in that shape. There may be other shapes that could work (ape for example would be a tenuous but possible choice), but for the majority of wild shape -> orc transformations it just will not work.
Of course, in the end, it would be up to the DM to decide how strictly they want to interpret what is or is not the same "body type" or "arrangement of limbs". A sufficiently lenient interpretation may open up options. See this Q&A for further discussion on this point.
Seeming would probably be suppressed until the druid returned to its original shape (DM decision)
At that point it is not entirely clear RAW what would happen to the spell since the druid has effectively become disqualified to receive the benefits of the spell as it was cast.
However it seems a reasonable way to handle this is to say that since the druid has changed into a form incompatible with the way the spell was cast, the spell had no effect while it's in that shape. However as long as the spell is maintained, there is no reason that the spell can't regain effect once the druid becomes a valid shape again.
Jeremy Crawford offers the same suggestion in response to a somewhat similar question:
In the end, as this is a gap in the rules, the DM will have to decide if they take this suggestion or rule instead that the spell is dispelled.