Excuseer is accepted. Excuseer mij is not wrong, but sounds a bit awkward if you ask me. I'm not too sure about usage in Belgium, but in the Netherlands excuseer isn't commonly used, if this verb is used, it's usually in formal settings then it is common not to drop any words or use an imperative (like in your example) but rather make a bit more extensive sentence: Excuseert u mij, which is closer to English If you could excuse me.
Also, there's nothing wrong with using a French loanword every now and then, English speakers should know. ;)
'Neem mij niet kwalijk' (without the 'het') can be used instead or 'sorry' or 'pardon' or before you want to ask something ('Neem mij niet kwalijk, maar kan u mij vertellen waar de winkel is' = 'Excuse me, can you tell me where the sotre is') of when you want to pass somebody, but there is not enough space. Or when you are to late: 'Neem mij niet kwalijk dat ik te laat ben.' = 'Excuse me for being late' But it is rather old fashioned.
'Neem het mij niet kwalijk' (with the 'het') can also be used to say sorry when you did something wrong en hope they want blame you or be angry. 'Neem mij niet kwalijk dat ik te laat ben' = 'Excuse me for being late' But with the 'het' most people will not use it just to ask if you can pass or just to say sorry.
Where you would use 'excuse me' in English, I would never translate ik in 'neem het mij niet kwalijk'.