Mark is right, you don't want to wait to invest. Your investments are like a snowball that gets bigger the longer it rolls, so the sooner you get it moving the better. And sometimes financial advisors don't always have the best advice.
As for multiple lenders, it couldn't hurt because when you lay out your financial picture, they can rather quickly tell you what you will and won't qualify for. Now, they do check your credit to give you an idea of what your credit score is but you can mitigate that as well. If you show up with all of your financial package lined up as in "this is how much I make per month, this is how much my total debt service is per month and my total expenses, and this is my FICO score. Without running my credit and giving me a ding for the check, can you give me an approximate amount of how much house I could qualify for just so I can get an idea of where I am and where I need to be?" I helped my cousin do this exact thing and though he was told he wasn't ready, they quite willingly laid out a plan that had him on track in less than six months and he was able to purchase his own house. If you do this, you can take advantage of a lot of programs available to homeowners that aren't available to investors.