Up to 75% - 80% LTV mostly depending on the rent roll / operating history of the property along with the lender's appetite.  

For example, a hotel requires a number of fire hazard improvements that would normally not be required of a residence -such as a fire suppression sprinkler system.

For the past 10 years they are 1 month behind with rent and always pay $100 late fee on their $2k rent.We are diligent with collecting rent on time with all of our other properties (residential) but only put up with this from the commercial tenant as the commercial market for this property has been soft/weak for the past 15 years and we have no appetite to have the property sit vacant for a year or two to prove a point.

The Fire suppression should be $3-$4 per square foot of sprinkled space

makes all the sense in the world until you find out that my local banks have absolutely no appetite for anything beyond 10 year cash out refi.  

I'd like to partner up with a friend who is also a recent graduate, former marine, and who has greater personable skills to complement my operational knowledge (developing procedures and guidelines in order to make consistently well informed decisions).I have a pretty considerable appetite for risk.

I believe the most important point in your decision is figuring out your appetite for risk.

Does this 4 plex already have a full fire suppression (sprinkler) and interconnected fire alarm systems?

Lower suppressed SFR in the same zip code.

When this is combined with a work/live situation I've found they've either carefully cared for, albeit sometime with wacky taste, or have substantial deferred maintenance.CRE investors, in general, don't have an appetite for investments like those described by you and above.