1) I'm not 100% certain I understand your question, but... you can make a $5500 contribution every year towards your IRA. It can be either a tIRA, a Roth IRA, or a combination, but the maximum per-adult is $5500.
Rolling over money from a 401(k) into an IRA does not count as part of your annual contribution. You can roll over $100k and still contribute $5,500 that year.
Did that answer your question
2) . Yes. For a variety of reasons Vanguard is very popular here, but you can contribute any post-tax dollars in whatever amount you like at whatever frequency suits you at any of the various brokerages around. I'd recommend setting up an auto-contribution that deducts the same time as your paycheck, but that's just me.
Here's why Vanguard is so popular around these parts. Fidelity has fans too, and some people like BEtterment for their robo-advising and loss harvesting (though that is also available elsewhere). What's important is that its a brokerage that you are comfortable with, that is transparent, and whos fees are very low (≤0.05% for domestic equity indexes, ≤0.15% for mixed/lifestyle/target-date funds. Some international funds may go as high as 0.20% for tax reasons, but if
any fund is asking for 0.40% or more in fees
run away.)
3) this is a deeply personal question. How solid is your job? Are you really the sort that can watch your equities portfolio lose 35% of its value in a matter of months and do nothing? Do you have any large-ticket itemds to pay for in the next 2 years? How many 'layers of safety' do you have with your revenue streams (e.g. side gigs, overtime opportunities, rental income, family savings, ability to cut back your budget, disability insurance, etc). All those factor into how much you'd want to keep in bonds. Some (myself included) have >90% of our liquid assets in equites. Others like to hold anywhere from 20-40% in bonds. There is no right answer of even a hive answer on this - it depends on oyu and your circumstances and your level of comfort with gains and loses.
